Search | arXiv e-print repository

<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"/> <meta name="viewport" content="width=device-width, initial-scale=1"/>  <link rel="apple-touch-icon" sizes="180x180" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/apple-touch-icon.png"> <link rel="icon" type="image/png" sizes="32x32" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon-32x32.png"> <link rel="icon" type="image/png" sizes="16x16" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon-16x16.png"> <link rel="manifest" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/site.webmanifest"> <link rel="mask-icon" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/safari-pinned-tab.svg" color="#b31b1b"> <link rel="shortcut icon" href="https://static.arxiv.org/static/base/1.0.0a5/images/icons/favicon.ico"> <meta name="msapplication-TileColor" content="#b31b1b"> <meta name="msapplication-config" content="images/icons/browserconfig.xml"> <meta name="theme-color" content="#b31b1b">  <title>Search | arXiv e-print repository</title> <script defer src="https://static.arxiv.org/static/base/1.0.0a5/fontawesome-free-5.11.2-web/js/all.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/base/1.0.0a5/css/arxivstyle.css" /> <script type="text/x-mathjax-config"> MathJax.Hub.Config({ messageStyle: "none", extensions: ["tex2jax.js"], jax: ["input/TeX", "output/HTML-CSS"], tex2jax: { inlineMath: [ ['$','$'], ["\$","\$"] ], displayMath: [ ['$$','$$'], ["\\[","\\]"] ], processEscapes: true, ignoreClass: '.*', processClass: 'mathjax.*' }, TeX: { extensions: ["AMSmath.js", "AMSsymbols.js", "noErrors.js"], noErrors: { inlineDelimiters: ["$","$"], multiLine: false, style: { "font-size": "normal", "border": "" } } }, "HTML-CSS": { availableFonts: ["TeX"] } }); </script> <script src='//static.arxiv.org/MathJax-2.7.3/MathJax.js'></script> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/notification.js"></script> <link rel="stylesheet" href="https://static.arxiv.org/static/search/0.5.6/css/bulma-tooltip.min.css" /> <link rel="stylesheet" href="https://static.arxiv.org/static/search/0.5.6/css/search.css" /> <script src="https://code.jquery.com/jquery-3.2.1.slim.min.js" integrity="sha256-k2WSCIexGzOj3Euiig+TlR8gA0EmPjuc79OEeY5L45g=" crossorigin="anonymous"></script> <script src="https://static.arxiv.org/static/search/0.5.6/js/fieldset.js"></script> <style> radio#cf-customfield_11400 { display: none; } </style> </head> <body> <header><a href="#main-container" class="is-sr-only">Skip to main content</a>  <div class="attribution level is-marginless" role="banner"> <div class="level-left"> <a class="level-item" href="https://cornell.edu/"><img src="https://static.arxiv.org/static/base/1.0.0a5/images/cornell-reduced-white-SMALL.svg" alt="Cornell University" width="200" aria-label="logo" /></a> </div> <div class="level-right is-marginless"><p class="sponsors level-item is-marginless"><span id="support-ack-url">We gratefully acknowledge support from<br /> the Simons Foundation, <a href="https://info.arxiv.org/about/ourmembers.html">member institutions</a>, and all contributors. <a href="https://info.arxiv.org/about/donate.html">Donate</a></span></p></div> </div>  <div class="identity level is-marginless"> <div class="level-left"> <div class="level-item"> <a class="arxiv" href="https://arxiv.org/" aria-label="arxiv-logo"> <img src="https://static.arxiv.org/static/base/1.0.0a5/images/arxiv-logo-one-color-white.svg" aria-label="logo" alt="arxiv logo" width="85" style="width:85px;"/> </a> </div> </div> <div class="search-block level-right"> <form class="level-item mini-search" method="GET" action="https://arxiv.org/search"> <div class="field has-addons"> <div class="control"> <input class="input is-small" type="text" name="query" placeholder="Search..." aria-label="Search term or terms" /> <p class="help"><a href="https://info.arxiv.org/help">Help</a> | <a href="https://arxiv.org/search/advanced">Advanced Search</a></p> </div> <div class="control"> <div class="select is-small"> <select name="searchtype" aria-label="Field to search"> <option value="all" selected="selected">All fields</option> <option value="title">Title</option> <option value="author">Author</option> <option value="abstract">Abstract</option> <option value="comments">Comments</option> <option value="journal_ref">Journal reference</option> <option value="acm_class">ACM classification</option> <option value="msc_class">MSC classification</option> <option value="report_num">Report number</option> <option value="paper_id">arXiv identifier</option> <option value="doi">DOI</option> <option value="orcid">ORCID</option> <option value="author_id">arXiv author ID</option> <option value="help">Help pages</option> <option value="full_text">Full text</option> </select> </div> </div> <input type="hidden" name="source" value="header"> <button class="button is-small is-cul-darker">Search</button> </div> </form> </div> </div>  <div class="container"> <div class="user-tools is-size-7 has-text-right has-text-weight-bold" role="navigation" aria-label="User menu"> <a href="https://arxiv.org/login">Login</a> </div> </div> </header> <main class="container" id="main-container"> <div class="level is-marginless"> <div class="level-left"> <h1 class="title is-clearfix"> Showing 1–50 of 55 results for author: <span class="mathjax">Zhukov, A N</span> </h1> </div> <div class="level-right is-hidden-mobile">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> <div class="content"> <form method="GET" action="/search/astro-ph" aria-role="search"> Searching in archive <strong>astro-ph</strong>. <a href="/search/?searchtype=author&query=Zhukov%2C+A+N">Search in all archives.</a> <div class="field has-addons-tablet"> <div class="control is-expanded"> <label for="query" class="hidden-label">Search term or terms</label> <input class="input is-medium" id="query" name="query" placeholder="Search term..." type="text" value="Zhukov, A N"> </div> <div class="select control is-medium"> <label class="is-hidden" for="searchtype">Field</label> <select class="is-medium" id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> </div> <div class="control"> <button class="button is-link is-medium">Search</button> </div> </div> <div class="field"> <div class="control is-size-7"> <label class="radio"> <input checked id="abstracts-0" name="abstracts" type="radio" value="show"> Show abstracts </label> <label class="radio"> <input id="abstracts-1" name="abstracts" type="radio" value="hide"> Hide abstracts </label> </div> </div> <div class="is-clearfix" style="height: 2.5em"> <div class="is-pulled-right"> <a href="/search/advanced?terms-0-term=Zhukov%2C+A+N&terms-0-field=author&size=50&order=-announced_date_first">Advanced Search</a> </div> </div> <input type="hidden" name="order" value="-announced_date_first"> <input type="hidden" name="size" value="50"> </form> <div class="level breathe-horizontal"> <div class="level-left"> <form method="GET" action="/search/"> <div style="display: none;"> <select id="searchtype" name="searchtype"><option value="all">All fields</option><option value="title">Title</option><option selected value="author">Author(s)</option><option value="abstract">Abstract</option><option value="comments">Comments</option><option value="journal_ref">Journal reference</option><option value="acm_class">ACM classification</option><option value="msc_class">MSC classification</option><option value="report_num">Report number</option><option value="paper_id">arXiv identifier</option><option value="doi">DOI</option><option value="orcid">ORCID</option><option value="license">License (URI)</option><option value="author_id">arXiv author ID</option><option value="help">Help pages</option><option value="full_text">Full text</option></select> <input id="query" name="query" type="text" value="Zhukov, A N"> <ul id="abstracts"><li><input checked id="abstracts-0" name="abstracts" type="radio" value="show"> <label for="abstracts-0">Show abstracts</label></li><li><input id="abstracts-1" name="abstracts" type="radio" value="hide"> <label for="abstracts-1">Hide abstracts</label></li></ul> </div> <div class="box field is-grouped is-grouped-multiline level-item"> <div class="control"> <span class="select is-small"> <select id="size" name="size"><option value="25">25</option><option selected value="50">50</option><option value="100">100</option><option value="200">200</option></select> </span> <label for="size">results per page</label>. </div> <div class="control"> <label for="order">Sort results by</label> <span class="select is-small"> <select id="order" name="order"><option selected value="-announced_date_first">Announcement date (newest first)</option><option value="announced_date_first">Announcement date (oldest first)</option><option value="-submitted_date">Submission date (newest first)</option><option value="submitted_date">Submission date (oldest first)</option><option value="">Relevance</option></select> </span> </div> <div class="control"> <button class="button is-small is-link">Go</button> </div> </div> </form> </div> </div> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Zhukov%2C+A+N&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Zhukov%2C+A+N&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhukov%2C+A+N&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.16513">arXiv:2411.16513</a> <span> [<a href="https://arxiv.org/pdf/2411.16513">pdf</a>, <a href="https://arxiv.org/format/2411.16513">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> </div> <p class="title is-5 mathjax"> Coronal hole picoflare jets are the progenitors of both the fast and the Alfv茅nic slow solar wind </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Huang%2C+Z">Z. Huang</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Amicis%2C+R">R. D'Amicis</a>, <a href="/search/astro-ph?searchtype=author&query=Calchetti%2C+D">D. Calchetti</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Hirzberger%2C+J">J. Hirzberger</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Horbury%2C+T+S">T. S. Horbury</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Owen%2C+C+J">C. J. Owen</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Louarn%2C+P">P. Louarn</a>, <a href="/search/astro-ph?searchtype=author&query=Livi%2C+S">S. Livi</a>, <a href="/search/astro-ph?searchtype=author&query=Giunta%2C+A+S">A. S. Giunta</a>, <a href="/search/astro-ph?searchtype=author&query=Hassler%2C+D+M">D. M. Hassler</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+Y+-">Y. -M. Wang</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.16513v1-abstract-short" style="display: inline;"> The solar wind, classified by its bulk speed and the Alfv茅nic nature of its fluctuations, generates the heliosphere. The elusive physical processes responsible for the generation of the different types of the wind are a topic of active debate. Recent observations revealed intermittent jets with kinetic energy in the picoflare range, emerging from dark areas of a polar coronal hole threaded by open… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.16513v1-abstract-full').style.display = 'inline'; document.getElementById('2411.16513v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.16513v1-abstract-full" style="display: none;"> The solar wind, classified by its bulk speed and the Alfv茅nic nature of its fluctuations, generates the heliosphere. The elusive physical processes responsible for the generation of the different types of the wind are a topic of active debate. Recent observations revealed intermittent jets with kinetic energy in the picoflare range, emerging from dark areas of a polar coronal hole threaded by open magnetic field lines. These could substantially contribute to the solar wind. However, their ubiquity and direct links to the solar wind have not been established. Here we report a unique set of remote-sensing and in-situ observations from the Solar Orbiter spacecraft, that establish a unified picture of the fast and Alfv茅nic slow wind, connected to the similar widespread picoflare jet activity in two coronal holes. Radial expansion of coronal holes ultimately regulates the speed of the emerging wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.16513v1-abstract-full').style.display = 'none'; document.getElementById('2411.16513v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 25 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in Astronomy and Astrophysics. Online animations available at https://owncloud.gwdg.de/index.php/s/ytjcW4Um1I6W2oZ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.00467">arXiv:2411.00467</a> <span> [<a href="https://arxiv.org/pdf/2411.00467">pdf</a>, <a href="https://arxiv.org/ps/2411.00467">ps</a>, <a href="https://arxiv.org/format/2411.00467">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346886">10.1051/0004-6361/202346886 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Spatial distributions of EUV brightenings in the quiet-Sun </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nelson%2C+C+J">C. J. Nelson</a>, <a href="/search/astro-ph?searchtype=author&query=Hayes%2C+L+A">L. A. Hayes</a>, <a href="/search/astro-ph?searchtype=author&query=M%C3%BCller%2C+D">D. M眉ller</a>, <a href="/search/astro-ph?searchtype=author&query=Musset%2C+S">S. Musset</a>, <a href="/search/astro-ph?searchtype=author&query=Freij%2C+N">N. Freij</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+E">E. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P">P. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.00467v1-abstract-short" style="display: inline;"> The identification of large numbers of localised transient EUV brightenings, with small spatial scales, in the quiet-Sun corona has been one of the key early results from Solar Orbiter. However, much is still unknown about these events. Here, we aim to better understand EUV brightenings by investigating their spatial distributions, specifically whether they occur co-spatial with specific line-of-s… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00467v1-abstract-full').style.display = 'inline'; document.getElementById('2411.00467v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.00467v1-abstract-full" style="display: none;"> The identification of large numbers of localised transient EUV brightenings, with small spatial scales, in the quiet-Sun corona has been one of the key early results from Solar Orbiter. However, much is still unknown about these events. Here, we aim to better understand EUV brightenings by investigating their spatial distributions, specifically whether they occur co-spatial with specific line-of-sight magnetic field topologies in the photospheric network. EUV brightenings are detected using an automated algorithm applied to a high-cadence (3 s) dataset sampled over ~30 min on 8 March 2022 by the Extreme Ultraviolet Imager's 17.4 nm EUV High Resolution Imager. Data from the Solar Dynamics Observatory's Helioseismic and Magnetic Imager and Atmospheric Imaging Assembly are used to provide context about the line-of-sight magnetic field and for alignment purposes. We found a total of 5064 EUV brightenings within this dataset that are directly comparable to events reported previously in the literature. These events occurred within around 0.015-0.020 % of pixels for any given frame. We compared eight different thresholds to split the EUV brightenings into four different categories related to the line-of-sight magnetic field. Using our preferred threshold, we found that 627 EUV brightenings (12.4 %) occurred co-spatial with Strong Bipolar configurations and 967 EUV brightenings (19.1 %) occurred in Weak Field regions. Fewer than 10 % of EUV brightenings occurred co-spatial with Unipolar line-of-sight magnetic field no matter what threshold was used. Of the 627 Strong Bipolar EUV Brightenings, 54 were found to occur co-spatial with cancellation whilst 57 occurred co-spatial with emergence. EUV brightenings preferentially occur co-spatial with the strong line-of-sight magnetic field in the photospheric network. They do not, though, predominantly occur co-spatial with (cancelling) bi-poles. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.00467v1-abstract-full').style.display = 'none'; document.getElementById('2411.00467v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 8 figures, accepted in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 692, A236 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2405.08196">arXiv:2405.08196</a> <span> [<a href="https://arxiv.org/pdf/2405.08196">pdf</a>, <a href="https://arxiv.org/format/2405.08196">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad7465">10.3847/1538-4357/ad7465 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fully Kinetic Simulations of Proton-Beam-Driven Instabilities from Parker Solar Probe Observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Pezzini%2C+L">Luca Pezzini</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Bacchini%2C+F">Fabio Bacchini</a>, <a href="/search/astro-ph?searchtype=author&query=Arr%C3%B2%2C+G">Giuseppe Arr貌</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez%2C+R+A">Rodrigo A. L贸pez</a>, <a href="/search/astro-ph?searchtype=author&query=Micera%2C+A">Alfredo Micera</a>, <a href="/search/astro-ph?searchtype=author&query=Innocenti%2C+M+E">Maria Elena Innocenti</a>, <a href="/search/astro-ph?searchtype=author&query=Lapenta%2C+G">Giovanni Lapenta</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2405.08196v2-abstract-short" style="display: inline;"> The expanding solar wind plasma ubiquitously exhibits anisotropic non-thermal particle velocity distributions. Typically, proton Velocity Distribution Functions (VDFs) show the presence of a core and a field-aligned beam. Novel observations made by Parker Solar Probe (PSP) in the innermost heliosphere have revealed new complex features in the proton VDFs, namely anisotropic beams that sometimes ex… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.08196v2-abstract-full').style.display = 'inline'; document.getElementById('2405.08196v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2405.08196v2-abstract-full" style="display: none;"> The expanding solar wind plasma ubiquitously exhibits anisotropic non-thermal particle velocity distributions. Typically, proton Velocity Distribution Functions (VDFs) show the presence of a core and a field-aligned beam. Novel observations made by Parker Solar Probe (PSP) in the innermost heliosphere have revealed new complex features in the proton VDFs, namely anisotropic beams that sometimes experience perpendicular diffusion. In this study, we use a 2.5D fully kinetic simulation to investigate the stability of proton VDFs with anisotropic beams observed by PSP. Our setup consists of a core and an anisotropic beam populations that drift with respect to each other. This configuration triggers a proton-beam instability from which nearly parallel fast magnetosonic modes develop. Our results demonstrate that before this instability reaches saturation, the waves resonantly interact with the beam protons, causing perpendicular heating at the expense of the parallel temperature. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2405.08196v2-abstract-full').style.display = 'none'; document.getElementById('2405.08196v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 May, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, 975:37, 2024 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2401.01875">arXiv:2401.01875</a> <span> [<a href="https://arxiv.org/pdf/2401.01875">pdf</a>, <a href="https://arxiv.org/format/2401.01875">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ad1ab4">10.3847/1538-4357/ad1ab4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the Mesoscale Structure of CMEs at Mercury's Orbit: BepiColombo and Parker Solar Probe Observations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Carcaboso%2C+F">Fernando Carcaboso</a>, <a href="/search/astro-ph?searchtype=author&query=Khoo%2C+L+Y">Leng Ying Khoo</a>, <a href="/search/astro-ph?searchtype=author&query=Salman%2C+T+M">Tarik M. Salman</a>, <a href="/search/astro-ph?searchtype=author&query=S%C3%A1nchez-Cano%2C+B">Beatriz S谩nchez-Cano</a>, <a href="/search/astro-ph?searchtype=author&query=Lynch%2C+B+J">Benjamin J. Lynch</a>, <a href="/search/astro-ph?searchtype=author&query=Rivera%2C+Y+J">Yeimy J. Rivera</a>, <a href="/search/astro-ph?searchtype=author&query=Pal%2C+S">Sanchita Pal</a>, <a href="/search/astro-ph?searchtype=author&query=Nieves-Chinchilla%2C+T">Teresa Nieves-Chinchilla</a>, <a href="/search/astro-ph?searchtype=author&query=Weiss%2C+A+J">Andreas J. Weiss</a>, <a href="/search/astro-ph?searchtype=author&query=Lario%2C+D">David Lario</a>, <a href="/search/astro-ph?searchtype=author&query=Mieth%2C+J+Z+D">Johannes Z. D. Mieth</a>, <a href="/search/astro-ph?searchtype=author&query=Heyner%2C+D">Daniel Heyner</a>, <a href="/search/astro-ph?searchtype=author&query=Stevens%2C+M+L">Michael L. Stevens</a>, <a href="/search/astro-ph?searchtype=author&query=Romeo%2C+O+M">Orlando M. Romeo</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Lee%2C+C+O">Christina O. Lee</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+C+M+S">Christina M. S. Cohen</a>, <a href="/search/astro-ph?searchtype=author&query=Rodr%C3%ADguez-Garc%C3%ADa%2C+L">Laura Rodr铆guez-Garc铆a</a>, <a href="/search/astro-ph?searchtype=author&query=Whittlesey%2C+P+L">Phyllis L. Whittlesey</a>, <a href="/search/astro-ph?searchtype=author&query=Dresing%2C+N">Nina Dresing</a>, <a href="/search/astro-ph?searchtype=author&query=Oleynik%2C+P">Philipp Oleynik</a>, <a href="/search/astro-ph?searchtype=author&query=Jebaraj%2C+I+C">Immanuel C. Jebaraj</a>, <a href="/search/astro-ph?searchtype=author&query=Fischer%2C+D">David Fischer</a> , et al. (5 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2401.01875v1-abstract-short" style="display: inline;"> On 2022 February 15, an impressive filament eruption was observed off the solar eastern limb from three remote-sensing viewpoints, namely Earth, STEREO-A, and Solar Orbiter. In addition to representing the most-distant observed filament at extreme ultraviolet wavelengths -- captured by Solar Orbiter's field of view extending to above 6 $R_{\odot}$ -- this event was also associated with the release… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01875v1-abstract-full').style.display = 'inline'; document.getElementById('2401.01875v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.01875v1-abstract-full" style="display: none;"> On 2022 February 15, an impressive filament eruption was observed off the solar eastern limb from three remote-sensing viewpoints, namely Earth, STEREO-A, and Solar Orbiter. In addition to representing the most-distant observed filament at extreme ultraviolet wavelengths -- captured by Solar Orbiter's field of view extending to above 6 $R_{\odot}$ -- this event was also associated with the release of a fast ($\sim$2200 km$\cdot$s$^{-1}$) coronal mass ejection (CME) that was directed towards BepiColombo and Parker Solar Probe. These two probes were separated by 2$^{\circ}$ in latitude, 4$^{\circ}$ in longitude, and 0.03 au in radial distance around the time of the CME-driven shock arrival in situ. The relative proximity of the two probes to each other and to the Sun ($\sim$0.35 au) allows us to study the mesoscale structure of CMEs at Mercury's orbit for the first time. We analyse similarities and differences in the main CME-related structures measured at the two locations, namely the interplanetary shock, the sheath region, and the magnetic ejecta. We find that, despite the separation between the two spacecraft being well within the typical uncertainties associated with determination of CME geometric parameters from remote-sensing observations, the two sets of in-situ measurements display some profound differences that make understanding of the overall 3D CME structure particularly challenging. Finally, we discuss our findings within the context of space weather at Mercury's distances and in terms of the need to investigate solar transients via spacecraft constellations with small separations, which has been gaining significant attention during recent years. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.01875v1-abstract-full').style.display = 'none'; document.getElementById('2401.01875v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 3 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2024. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">31 pages, 13 figures, 5 tables, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.09789">arXiv:2309.09789</a> <span> [<a href="https://arxiv.org/pdf/2309.09789">pdf</a>, <a href="https://arxiv.org/format/2309.09789">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346040">10.1051/0004-6361/202346040 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coronal voids and their magnetic nature </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=N%C3%B6lke%2C+J+D">J. D. N枚lke</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Hirzberger%2C+J">J. Hirzberger</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Kahil%2C+F">F. Kahil</a>, <a href="/search/astro-ph?searchtype=author&query=Valori%2C+G">G. Valori</a>, <a href="/search/astro-ph?searchtype=author&query=Wiegelmann%2C+T">T. Wiegelmann</a>, <a href="/search/astro-ph?searchtype=author&query=Su%C3%A1rez%2C+D+O">D. Orozco Su谩rez</a>, <a href="/search/astro-ph?searchtype=author&query=Albert%2C+K">K. Albert</a>, <a href="/search/astro-ph?searchtype=author&query=Jorge%2C+N+A">N. Albelo Jorge</a>, <a href="/search/astro-ph?searchtype=author&query=Appourchaux%2C+T">T. Appourchaux</a>, <a href="/search/astro-ph?searchtype=author&query=Alvarez-Herrero%2C+A">A. Alvarez-Herrero</a>, <a href="/search/astro-ph?searchtype=author&query=Rodr%C3%ADguez%2C+J+B">J. Blanco Rodr铆guez</a>, <a href="/search/astro-ph?searchtype=author&query=Gandorfer%2C+A">A. Gandorfer</a>, <a href="/search/astro-ph?searchtype=author&query=Germerott%2C+D">D. Germerott</a>, <a href="/search/astro-ph?searchtype=author&query=Guerrero%2C+L">L. Guerrero</a>, <a href="/search/astro-ph?searchtype=author&query=Gutierrez-Marques%2C+P">P. Gutierrez-Marques</a>, <a href="/search/astro-ph?searchtype=author&query=Kolleck%2C+M">M. Kolleck</a>, <a href="/search/astro-ph?searchtype=author&query=Iniesta%2C+J+C+d+T">J. C. del Toro Iniesta</a>, <a href="/search/astro-ph?searchtype=author&query=Volkmer%2C+R">R. Volkmer</a>, <a href="/search/astro-ph?searchtype=author&query=Woch%2C+J">J. Woch</a>, <a href="/search/astro-ph?searchtype=author&query=Fiethe%2C+B">B. Fiethe</a>, <a href="/search/astro-ph?searchtype=author&query=Cama%2C+J+M+G">J. M. G贸mez Cama</a>, <a href="/search/astro-ph?searchtype=author&query=P%C3%A9rez-Grande%2C+I">I. P茅rez-Grande</a> , et al. (46 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.09789v1-abstract-short" style="display: inline;"> Extreme ultraviolet (EUV) observations of the quiet solar atmosphere reveal extended regions of weak emission compared to the ambient quiescent corona. The magnetic nature of these coronal features is not well understood. We study the magnetic properties of the weakly emitting extended regions, which we name coronal voids. In particular, we aim to understand whether these voids result from a reduc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.09789v1-abstract-full').style.display = 'inline'; document.getElementById('2309.09789v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.09789v1-abstract-full" style="display: none;"> Extreme ultraviolet (EUV) observations of the quiet solar atmosphere reveal extended regions of weak emission compared to the ambient quiescent corona. The magnetic nature of these coronal features is not well understood. We study the magnetic properties of the weakly emitting extended regions, which we name coronal voids. In particular, we aim to understand whether these voids result from a reduced heat input into the corona or if they are associated with mainly unipolar and possibly open magnetic fields, similar to coronal holes. We defined the coronal voids via an intensity threshold of 75% of the mean quiet-Sun (QS) EUV intensity observed by the high-resolution EUV channel (HRIEUV) of the Extreme Ultraviolet Imager on Solar Orbiter. The line-of-sight magnetograms of the same solar region recorded by the High Resolution Telescope of the Polarimetric and Helioseismic Imager allowed us to compare the photospheric magnetic field beneath the coronal voids with that in other parts of the QS. The coronal voids studied here range in size from a few granules to a few supergranules and on average exhibit a reduced intensity of 67% of the mean value of the entire field of view. The magnetic flux density in the photosphere below the voids is 76% (or more) lower than in the surrounding QS. Specifically, the coronal voids show much weaker or no network structures. The detected flux imbalances fall in the range of imbalances found in QS areas of the same size. Conclusions. We conclude that coronal voids form because of locally reduced heating of the corona due to reduced magnetic flux density in the photosphere. This makes them a distinct class of (dark) structure, different from coronal holes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.09789v1-abstract-full').style.display = 'none'; document.getElementById('2309.09789v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 11 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 678, A196 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.05101">arXiv:2309.05101</a> <span> [<a href="https://arxiv.org/pdf/2309.05101">pdf</a>, <a href="https://arxiv.org/format/2309.05101">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202347343">10.1051/0004-6361/202347343 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evolution of dynamic fibrils from the cooler chromosphere to the hotter corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">Sudip Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">Hardi Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">Lakshmi Pradeep Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">Sami K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">Regina Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">Udo Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">Luca Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Sykora%2C+J+M">Juan Mart铆nez Sykora</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">Fr茅d茅ric Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">Susanna Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡ric Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">Cis Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">Emil Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">Krzysztof Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Pelouze%2C+G">Gabriel Pelouze</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">Philip J. Smith</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2309.05101v1-abstract-short" style="display: inline;"> Dynamic fibrils (DFs) are commonly observed chromospheric features in solar active regions. Recent observations from the Extreme Ultraviolet Imager (EUI) aboard the Solar Orbiter have revealed unambiguous signatures of DFs at the coronal base, in extreme ultraviolet (EUV) emission. However, it remains unclear if the DFs detected in the EUV are linked to their chromospheric counterparts. Simultaneo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.05101v1-abstract-full').style.display = 'inline'; document.getElementById('2309.05101v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.05101v1-abstract-full" style="display: none;"> Dynamic fibrils (DFs) are commonly observed chromospheric features in solar active regions. Recent observations from the Extreme Ultraviolet Imager (EUI) aboard the Solar Orbiter have revealed unambiguous signatures of DFs at the coronal base, in extreme ultraviolet (EUV) emission. However, it remains unclear if the DFs detected in the EUV are linked to their chromospheric counterparts. Simultaneous detection of DFs from chromospheric to coronal temperatures could provide important information on their thermal structuring and evolution through the solar atmosphere. In this paper, we address this question by using coordinated EUV observations from the Atmospheric Imaging Assembly (AIA), Interface Region Imaging Spectrograph (IRIS), and EUI to establish a one-to-one correspondence between chromospheric and transition region DFs (observed by IRIS) with their coronal counterparts (observed by EUI and AIA). Our analysis confirms a close correspondence between DFs observed at different atmospheric layers, and reveals that DFs can reach temperatures of about 1.5 million Kelvin, typical of the coronal base in active regions. Furthermore, intensity evolution of these DFs, as measured by tracking them over time, reveals a shock-driven scenario in which plasma piles up near the tips of these DFs and, subsequently, these tips appear as bright blobs in coronal images. These findings provide information on the thermal structuring of DFs and their evolution and impact through the solar atmosphere. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.05101v1-abstract-full').style.display = 'none'; document.getElementById('2309.05101v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A Letters. Animation files are available https://drive.google.com/drive/folders/17-fqQz_P2T18llJ1jB6MJISMRvT5063F?usp=sharing</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 678, L5 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.14651">arXiv:2308.14651</a> <span> [<a href="https://arxiv.org/pdf/2308.14651">pdf</a>, <a href="https://arxiv.org/format/2308.14651">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> </div> <p class="title is-5 mathjax"> The eruption of a magnetic flux rope observed by \textit{Solar Orbiter} and \textit{Parker Solar Probe} </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Green%2C+L+M">Lucie M. Green</a>, <a href="/search/astro-ph?searchtype=author&query=Pecora%2C+F">Francesco Pecora</a>, <a href="/search/astro-ph?searchtype=author&query=Brooks%2C+D+H">David H. Brooks</a>, <a href="/search/astro-ph?searchtype=author&query=Strecker%2C+H">Hanna Strecker</a>, <a href="/search/astro-ph?searchtype=author&query=Orozco-Su%C3%A1rez%2C+D">David Orozco-Su谩rez</a>, <a href="/search/astro-ph?searchtype=author&query=Hayes%2C+L+A">Laura A. Hayes</a>, <a href="/search/astro-ph?searchtype=author&query=Davies%2C+E+E">Emma E. Davies</a>, <a href="/search/astro-ph?searchtype=author&query=Amerstorfer%2C+U+V">Ute V. Amerstorfer</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">Marilena Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Lario%2C+D">David Lario</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=R%C3%BCdisser%2C+H+T">Hannah T. R眉disser</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.14651v1-abstract-short" style="display: inline;"> Magnetic flux ropes are a key component of coronal mass ejections, forming the core of these eruptive phenomena. However, determining whether a flux rope is present prior to eruption onset and, if so, the rope's handedness and the number of turns that any helical field lines make is difficult without magnetic field modelling or in-situ detection of the flux rope. We present two distinct observatio… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.14651v1-abstract-full').style.display = 'inline'; document.getElementById('2308.14651v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.14651v1-abstract-full" style="display: none;"> Magnetic flux ropes are a key component of coronal mass ejections, forming the core of these eruptive phenomena. However, determining whether a flux rope is present prior to eruption onset and, if so, the rope's handedness and the number of turns that any helical field lines make is difficult without magnetic field modelling or in-situ detection of the flux rope. We present two distinct observations of plasma flows along a filament channel on 4 and 5 September 2022 made using the \textit{Solar Orbiter} spacecraft. Each plasma flow exhibited helical motions in a right-handed sense as the plasma moved from the source active region across the solar disk to the quiet Sun, suggesting that the magnetic configuration of the filament channel contains a flux rope with positive chirality and at least one turn. The length and velocity of the plasma flow increased from the first to the second observation, suggesting evolution of the flux rope, with the flux rope subsequently erupting within $\sim$5~hours of the second plasma flow. The erupting flux rope then passed over the \textit{Parker Solar Probe} spacecraft during its Encounter 13, enabling \textit{in-situ} diagnostics of the structure. Although complex and consistent with the flux rope erupting from underneath the heliospheric current sheet, the \textit{in-situ} measurements support the inference of a right-handed flux rope from remote-sensing observations. These observations provide a unique insight into the eruption and evolution of a magnetic flux rope near the Sun. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.14651v1-abstract-full').style.display = 'none'; document.getElementById('2308.14651v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">19 pages, 11 figures, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.13044">arXiv:2308.13044</a> <span> [<a href="https://arxiv.org/pdf/2308.13044">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1126/science.ade5801">10.1126/science.ade5801 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Picoflare jets power the solar wind emerging from a coronal hole on the Sun </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">C. Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Seaton%2C+D+B">D. B. Seaton</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.13044v1-abstract-short" style="display: inline;"> Coronal holes are areas on the Sun with open magnetic field lines. They are a source region of the solar wind, but how the wind emerges from coronal holes is not known. We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft. We identified jets on scales of a few hundred kilometers, which last 20 to 100 seconds and reach speeds of ~100 kilometers per second.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.13044v1-abstract-full').style.display = 'inline'; document.getElementById('2308.13044v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.13044v1-abstract-full" style="display: none;"> Coronal holes are areas on the Sun with open magnetic field lines. They are a source region of the solar wind, but how the wind emerges from coronal holes is not known. We observed a coronal hole using the Extreme Ultraviolet Imager on the Solar Orbiter spacecraft. We identified jets on scales of a few hundred kilometers, which last 20 to 100 seconds and reach speeds of ~100 kilometers per second. The jets are powered by magnetic reconnection and have kinetic energy in the picoflare range. They are intermittent but widespread within the observed coronal hole. We suggest that such picoflare jets could produce enough high-temperature plasma to sustain the solar wind and that the wind emerges from coronal holes as a highly intermittent outflow at small scales. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.13044v1-abstract-full').style.display = 'none'; document.getElementById('2308.13044v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">This is the author's version of the work. The definitive version was published in Science on 24 August 2023</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science 381, 867-872 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2308.10982">arXiv:2308.10982</a> <span> [<a href="https://arxiv.org/pdf/2308.10982">pdf</a>, <a href="https://arxiv.org/format/2308.10982">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/acf136">10.3847/2041-8213/acf136 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Fleeting Small-scale Surface Magnetic Fields Build the Quiet-Sun Corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Iniesta%2C+J+C+d+T">J. C. del Toro Iniesta</a>, <a href="/search/astro-ph?searchtype=author&query=Woch%2C+J">J. Woch</a>, <a href="/search/astro-ph?searchtype=author&query=Calchetti%2C+D">D. Calchetti</a>, <a href="/search/astro-ph?searchtype=author&query=Gandorfer%2C+A">A. Gandorfer</a>, <a href="/search/astro-ph?searchtype=author&query=Hirzberger%2C+J">J. Hirzberger</a>, <a href="/search/astro-ph?searchtype=author&query=Kahil%2C+F">F. Kahil</a>, <a href="/search/astro-ph?searchtype=author&query=Valori%2C+G">G. Valori</a>, <a href="/search/astro-ph?searchtype=author&query=Su%C3%A1rez%2C+D+O">D. Orozco Su谩rez</a>, <a href="/search/astro-ph?searchtype=author&query=Strecker%2C+H">H. Strecker</a>, <a href="/search/astro-ph?searchtype=author&query=Appourchaux%2C+T">T. Appourchaux</a>, <a href="/search/astro-ph?searchtype=author&query=Volkmer%2C+R">R. Volkmer</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Priest%2C+E+R">E. R. Priest</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2308.10982v2-abstract-short" style="display: inline;"> Arch-like loop structures filled with million Kelvin hot plasma form the building blocks of the quiet-Sun corona. Both high-resolution observations and magnetoconvection simulations show the ubiquitous presence of magnetic fields on the solar surface on small spatial scales of $\sim$100\,km. However, the question of how exactly these quiet-Sun coronal loops originate from the photosphere and how t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10982v2-abstract-full').style.display = 'inline'; document.getElementById('2308.10982v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2308.10982v2-abstract-full" style="display: none;"> Arch-like loop structures filled with million Kelvin hot plasma form the building blocks of the quiet-Sun corona. Both high-resolution observations and magnetoconvection simulations show the ubiquitous presence of magnetic fields on the solar surface on small spatial scales of $\sim$100\,km. However, the question of how exactly these quiet-Sun coronal loops originate from the photosphere and how the magnetic energy from the surface is channeled to heat the overlying atmosphere is a long-standing puzzle. Here we report high-resolution photospheric magnetic field and coronal data acquired during the second science perihelion of Solar Orbiter that reveal a highly dynamic magnetic landscape underlying the observed quiet-Sun corona. We found that coronal loops often connect to surface regions that harbor fleeting weaker, mixed-polarity magnetic field patches structured on small spatial scales, and that coronal disturbances could emerge from these areas. We suggest that weaker magnetic fields with fluxes as low as $10^{15}$\,Mx and/or those that evolve on timescales less than 5\,minutes, are crucial to understand the coronal structuring and dynamics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2308.10982v2-abstract-full').style.display = 'none'; document.getElementById('2308.10982v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published in The Astrophysical Journal Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJL 956, L1 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.05190">arXiv:2306.05190</a> <span> [<a href="https://arxiv.org/pdf/2306.05190">pdf</a>, <a href="https://arxiv.org/ps/2306.05190">ps</a>, <a href="https://arxiv.org/format/2306.05190">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346144">10.1051/0004-6361/202346144 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> EUV brightenings in the quiet-Sun: Signatures in spectral and imaging data from the Interface Region Imaging Spectrograph </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nelson%2C+C+J">C. J. Nelson</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+E">E. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">C. Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P">P. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2306.05190v1-abstract-short" style="display: inline;"> Localised transient EUV brightenings, sometimes named `campfires', occur throughout the quiet-Sun. However, there are still many open questions about such events, in particular regarding their temperature range and dynamics. In this article, we aim to determine whether any transition region response can be detected for small-scale EUV brightenings and, if so, to identify whether the measured spect… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.05190v1-abstract-full').style.display = 'inline'; document.getElementById('2306.05190v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.05190v1-abstract-full" style="display: none;"> Localised transient EUV brightenings, sometimes named `campfires', occur throughout the quiet-Sun. However, there are still many open questions about such events, in particular regarding their temperature range and dynamics. In this article, we aim to determine whether any transition region response can be detected for small-scale EUV brightenings and, if so, to identify whether the measured spectra correspond to any previously reported bursts in the transition region, such as Explosive Events (EEs). EUV brightenings were detected in a ~29.4 minute dataset sampled by Solar Orbiter's Extreme Ultraviolet Imager on 8 March 2022 using an automated detection algorithm. Any potential transition region response was inferred through analysis of imaging and spectral data sampled through coordinated observations conducted by the Interface Region Imaging Spectrograph (IRIS). EUV brightenings display a range of responses in IRIS slit-jaw imager (SJI) data. Some events have clear signatures in the Mg II and Si IV SJI filters, whilst others have no discernible counterpart. Both extended and more complex EUV brightenings are found to, sometimes, have responses in IRIS SJI data. Examples of EUI intensities peaking before, during, and after their IRIS counterparts were found in lightcurves constructed co-spatial to EUV brightenings. Importantly, therefore, it is likely that not all EUV brightenings are driven in the same way, with some seemingly being magnetic reconnection driven and others not. A single EUV brightening occurred co-spatial to the IRIS slit, with its spectra matching the properties of EEs. EUV brightenings is a term used to describe a range of small-scale event in the solar corona. The physics responsible for all EUV brightenings is likely not the same and, therefore, more research is required to assess their importance towards global questions in the field, such as coronal heating. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.05190v1-abstract-full').style.display = 'none'; document.getElementById('2306.05190v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted to A&A, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 676, A64 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.11691">arXiv:2305.11691</a> <span> [<a href="https://arxiv.org/pdf/2305.11691">pdf</a>, <a href="https://arxiv.org/format/2305.11691">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346016">10.1051/0004-6361/202346016 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> EUV fine structure and variability associated with coronal rain revealed by Solar Orbiter/EUI HRIEUV and SPICE </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">P. Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Dolliou%2C+A">A. Dolliou</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Huang%2C+Z">Z. Huang</a>, <a href="/search/astro-ph?searchtype=author&query=Janvier%2C+M">M. Janvier</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Stegen%2C+K">K. Stegen</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">M. J. West</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a> , et al. (12 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2305.11691v1-abstract-short" style="display: inline;"> Coronal rain is the most dramatic cooling phenomenon of the solar corona and an essential diagnostic tool for the coronal heating properties. A puzzling feature of the solar corona, besides the heating, is its EUV filamentary structure and variability. We aim to identify observable features of the TNE-TI scenario underlying coronal rain at small and large spatial scales, to understand the role it… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.11691v1-abstract-full').style.display = 'inline'; document.getElementById('2305.11691v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.11691v1-abstract-full" style="display: none;"> Coronal rain is the most dramatic cooling phenomenon of the solar corona and an essential diagnostic tool for the coronal heating properties. A puzzling feature of the solar corona, besides the heating, is its EUV filamentary structure and variability. We aim to identify observable features of the TNE-TI scenario underlying coronal rain at small and large spatial scales, to understand the role it plays in the solar corona. We use EUV datasets at unprecedented spatial resolution of ~240 km from EUI/HRIEUV and SPICE of Solar Orbiter from the spring 2022 perihelion. EUV absorption features produced by coronal rain are detected at scales as small as 260 km. As the rain falls, heating and compression is produced immediately downstream, leading to a small EUV brightening accompanying the fall and producing a "fireball" phenomenon. Just prior to impact, a flash-like EUV brightening downstream of the rain, lasting a few minutes is observed for the fastest events. For the first time, we detect the atmospheric response to the rain's impact on the chromosphere and consists of upward propagating rebound shocks and flows partly reheating the loop. The observed widths of the rain clumps are 500 +- 200 km. They exhibit a broad velocity distribution of 10 - 150 km s^-1, peaking below 50 km s^-1. Coronal strands of similar widths are observed along the same loops co-spatial with cool filamentary structure, which we interpret as the CCTR. Matching with the expected cooling, prior to the rain appearance sequential loop brightenings are detected in gradually cooler lines from corona to chromospheric temperatures. Despite the large rain showers, most cannot be detected in AIA 171 in quadrature, indicating that LOS effects play a major role in coronal rain visibility. Still, AIA 304 and SPICE observations reveal that only a small fraction of the rain can be captured by HRIEUV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.11691v1-abstract-full').style.display = 'none'; document.getElementById('2305.11691v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 19 May, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Astronomy & Astrophysics; 32 Pages, 24 Main Figures, Appendix</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 676, A112 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.13554">arXiv:2304.13554</a> <span> [<a href="https://arxiv.org/pdf/2304.13554">pdf</a>, <a href="https://arxiv.org/format/2304.13554">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202346670">10.1051/0004-6361/202346670 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Statistical Investigation of Decayless Oscillations in Small-scale Coronal Loops Observed by Solar Orbiter/EUI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Shrivastav%2C+A+K">Arpit Kumar Shrivastav</a>, <a href="/search/astro-ph?searchtype=author&query=Pant%2C+V">Vaibhav Pant</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Van+Doorsselaere%2C+T">Tom Van Doorsselaere</a>, <a href="/search/astro-ph?searchtype=author&query=Petrova%2C+E">Elena Petrova</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+D">Dipankar Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Lim%2C+D">Daye Lim</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">Cis Verbeeck</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.13554v3-abstract-short" style="display: inline;"> Decayless kink oscillations are omnipresent in the solar atmosphere and a viable candidate for coronal heating. Though there have been extensive studies of decayless oscillations in coronal loops with a few hundred Mm lengths, the properties of these oscillations in small-scale ($\sim$10 Mm) loops are yet to be explored. In this study, we present the properties of decayless oscillations in small l… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13554v3-abstract-full').style.display = 'inline'; document.getElementById('2304.13554v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.13554v3-abstract-full" style="display: none;"> Decayless kink oscillations are omnipresent in the solar atmosphere and a viable candidate for coronal heating. Though there have been extensive studies of decayless oscillations in coronal loops with a few hundred Mm lengths, the properties of these oscillations in small-scale ($\sim$10 Mm) loops are yet to be explored. In this study, we present the properties of decayless oscillations in small loops embedded in the quiet corona and coronal holes. We use high resolution observations from the Extreme Ultraviolet Imager onboard Solar Orbiter with pixel scales of 210 km and 5 s cadence or better. We find 42 oscillations in 33 coronal loops with loop lengths varying between 3 to 23 Mm. The average displacement amplitude is found to be 136 km. The oscillations period has a range of 27 to 276 s, and the velocity amplitudes range from 2.2 to 19.3 km s$^{-1}$. The observed kink speeds are lower than those observed in active region coronal loops. The variation of loop length with the period does not indicate a strong correlation. Coronal seismology technique indicated an average magnetic field value of 2.1 G. We estimate the energy flux with a broad range of 0.6-314 W m$^{-2}$. Moreover, we note that the short-period decayless oscillations are not prevalent in the quiet Sun and coronal holes. Therefore, our study suggests that decayless oscillations in small-scale coronal loops are unlikely to provide enough energy to heat the quiet Sun and accelerate solar wind in the coronal holes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.13554v3-abstract-full').style.display = 'none'; document.getElementById('2304.13554v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 January, 2024; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in the Astronomy & Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.09570">arXiv:2304.09570</a> <span> [<a href="https://arxiv.org/pdf/2304.09570">pdf</a>, <a href="https://arxiv.org/format/2304.09570">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4365/acd24b">10.3847/1538-4365/acd24b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Slow Solar Wind Connection Science during Solar Orbiter's First Close Perihelion Passage </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Yardley%2C+S+L">Stephanie L. Yardley</a>, <a href="/search/astro-ph?searchtype=author&query=Owen%2C+C+J">Christopher J. Owen</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Baker%2C+D">Deborah Baker</a>, <a href="/search/astro-ph?searchtype=author&query=Brooks%2C+D+H">David H. Brooks</a>, <a href="/search/astro-ph?searchtype=author&query=Polito%2C+V">Vanessa Polito</a>, <a href="/search/astro-ph?searchtype=author&query=Green%2C+L+M">Lucie M. Green</a>, <a href="/search/astro-ph?searchtype=author&query=Matthews%2C+S">Sarah Matthews</a>, <a href="/search/astro-ph?searchtype=author&query=Owens%2C+M">Mathew Owens</a>, <a href="/search/astro-ph?searchtype=author&query=Lockwood%2C+M">Mike Lockwood</a>, <a href="/search/astro-ph?searchtype=author&query=Stansby%2C+D">David Stansby</a>, <a href="/search/astro-ph?searchtype=author&query=James%2C+A+W">Alexander W. James</a>, <a href="/search/astro-ph?searchtype=author&query=Valori%2C+G">Gherado Valori</a>, <a href="/search/astro-ph?searchtype=author&query=Giunta%2C+A">Alessandra Giunta</a>, <a href="/search/astro-ph?searchtype=author&query=Janvier%2C+M">Miho Janvier</a>, <a href="/search/astro-ph?searchtype=author&query=Ngampoopun%2C+N">Nawin Ngampoopun</a>, <a href="/search/astro-ph?searchtype=author&query=Mihailescu%2C+T">Teodora Mihailescu</a>, <a href="/search/astro-ph?searchtype=author&query=To%2C+A+S+H">Andy S. H. To</a>, <a href="/search/astro-ph?searchtype=author&query=van+Driel-Gesztelyi%2C+L">Lidia van Driel-Gesztelyi</a>, <a href="/search/astro-ph?searchtype=author&query=Demoulin%2C+P">Pascal Demoulin</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Amicis%2C+R">Raffaella D'Amicis</a>, <a href="/search/astro-ph?searchtype=author&query=French%2C+R+J">Ryan J. French</a>, <a href="/search/astro-ph?searchtype=author&query=Suen%2C+G+H+H">Gabriel H. H. Suen</a>, <a href="/search/astro-ph?searchtype=author&query=Roulliard%2C+A+P">Alexis P. Roulliard</a>, <a href="/search/astro-ph?searchtype=author&query=Pinto%2C+R+F">Rui F. Pinto</a> , et al. (54 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.09570v2-abstract-short" style="display: inline;"> The Slow Solar Wind Connection Solar Orbiter Observing Plan (Slow Wind SOOP) was developed to utilise the extensive suite of remote sensing and in situ instruments on board the ESA/NASA Solar Orbiter mission to answer significant outstanding questions regarding the origin and formation of the slow solar wind. The Slow Wind SOOP was designed to link remote sensing and in situ measurements of slow w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.09570v2-abstract-full').style.display = 'inline'; document.getElementById('2304.09570v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.09570v2-abstract-full" style="display: none;"> The Slow Solar Wind Connection Solar Orbiter Observing Plan (Slow Wind SOOP) was developed to utilise the extensive suite of remote sensing and in situ instruments on board the ESA/NASA Solar Orbiter mission to answer significant outstanding questions regarding the origin and formation of the slow solar wind. The Slow Wind SOOP was designed to link remote sensing and in situ measurements of slow wind originating at open-closed field boundaries. The SOOP ran just prior to Solar Orbiter's first close perihelion passage during two remote sensing windows (RSW1 and RSW2) between 2022 March 3-6 and 2022 March 17-22, while Solar Orbiter was at a heliocentric distance of 0.55-0.51 and 0.38-0.34 au from the Sun, respectively. Coordinated observation campaigns were also conducted by Hinode and IRIS. The magnetic connectivity tool was used, along with low latency in situ data, and full-disk remote sensing observations, to guide the target pointing of Solar Orbiter. Solar Orbiter targeted an active region complex during RSW1, the boundary of a coronal hole, and the periphery of a decayed active region during RSW2. Post-observation analysis using the magnetic connectivity tool along with in situ measurements from MAG and SWA/PAS, show that slow solar wind, with velocities between 210 and 600 km/s, arrived at the spacecraft originating from two out of the three of the target regions. The Slow Wind SOOP, despite presenting many challenges, was very successful, providing a blueprint for planning future observation campaigns that rely on the magnetic connectivity of Solar Orbiter. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.09570v2-abstract-full').style.display = 'none'; document.getElementById('2304.09570v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">24 pages, 10 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.08725">arXiv:2304.08725</a> <span> [<a href="https://arxiv.org/pdf/2304.08725">pdf</a>, <a href="https://arxiv.org/format/2304.08725">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-023-37888-w">10.1038/s41467-023-37888-w <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ultra-high-resolution Observations of Persistent Null-point Reconnection in the Solar Corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Cheng%2C+X">X. Cheng</a>, <a href="/search/astro-ph?searchtype=author&query=Priest%2C+E+R">E. R. Priest</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+H+T">H. T. Li</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+J">J. Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Aulanier%2C+G">G. Aulanier</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+Y+L">Y. L. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Zhu%2C+X+S">X. S. Zhu</a>, <a href="/search/astro-ph?searchtype=author&query=Xing%2C+C">C. Xing</a>, <a href="/search/astro-ph?searchtype=author&query=Ding%2C+M+D">M. D. Ding</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Guo%2C+Y">Y. Guo</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D">D. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.08725v1-abstract-short" style="display: inline;"> Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.08725v1-abstract-full').style.display = 'inline'; document.getElementById('2304.08725v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.08725v1-abstract-full" style="display: none;"> Magnetic reconnection is a key mechanism involved in solar eruptions and is also a prime possibility to heat the low corona to millions of degrees. Here, we present ultra-high-resolution extreme ultraviolet observations of persistent null-point reconnection in the corona at a scale of about 390 km over one hour observations of the Extreme-Ultraviolet Imager on board Solar Orbiter spacecraft. The observations show formation of a null-point configuration above a minor positive polarity embedded within a region of dominant negative polarity near a sunspot. The gentle phase of the persistent null-point reconnection is evidenced by sustained point-like high-temperature plasma (about 10 MK) near the null-point and constant outflow blobs not only along the outer spine but also along the fan surface. The blobs appear at a higher frequency than previously observed with an average velocity of about 80 km/s and life-times of about 40 s. The null-point reconnection also occurs explosively but only for 4 minutes, its coupling with a mini-filament eruption generates a spiral jet. These results suggest that magnetic reconnection, at previously unresolved scales, proceeds continually in a gentle and/or explosive way to persistently transfer mass and energy to the overlying corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.08725v1-abstract-full').style.display = 'none'; document.getElementById('2304.08725v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 18 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 7 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.16046">arXiv:2303.16046</a> <span> [<a href="https://arxiv.org/pdf/2303.16046">pdf</a>, <a href="https://arxiv.org/format/2303.16046">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202245814">10.1051/0004-6361/202245814 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Evidence of external reconnection between an erupting mini-filament and ambient loops observed by Solar Orbiter/EUI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Li%2C+Z+F">Z. F. Li</a>, <a href="/search/astro-ph?searchtype=author&query=Cheng%2C+X">X. Cheng</a>, <a href="/search/astro-ph?searchtype=author&query=Ding%2C+M+D">M. D. Ding</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Auchere%2C+F">F. Auchere</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Schuehle%2C+U">U. Schuehle</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+E">E. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.16046v1-abstract-short" style="display: inline;"> Mini-filament eruptions are one of the most common small-scale transients in the solar atmosphere. However, their eruption mechanisms are still not understood thoroughly. Here, with a combination of 174 A images of high spatio-temporal resolution taken by the Extreme Ultraviolet Imager on board Solar Orbiter and images of the Atmospheric Imaging Assembly on board Solar Dynamics Observatory, we inv… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.16046v1-abstract-full').style.display = 'inline'; document.getElementById('2303.16046v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.16046v1-abstract-full" style="display: none;"> Mini-filament eruptions are one of the most common small-scale transients in the solar atmosphere. However, their eruption mechanisms are still not understood thoroughly. Here, with a combination of 174 A images of high spatio-temporal resolution taken by the Extreme Ultraviolet Imager on board Solar Orbiter and images of the Atmospheric Imaging Assembly on board Solar Dynamics Observatory, we investigate in detail an erupting mini-filament over a weak magnetic field region on 2022 March 4. Two bright ribbons clearly appeared underneath the erupting mini-filament as it quickly ascended, and subsequently, some dark materials blew out when the erupting mini-filament interacted with the outer ambient loops, thus forming a blowout jet characterized by a widening spire. At the same time, multiple small bright blobs of 1-2 Mm appeared at the interaction region and propagated along the post-eruption loops toward the footpoints of the erupting fluxes at a speed of ~ 100 km/s. They also caused a semi-circular brightening structure. Based on these features, we suggest that the mini-filament eruption first experiences internal and then external reconnection, the latter of which mainly transfers mass and magnetic flux of the erupting mini-filament to the ambient corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.16046v1-abstract-full').style.display = 'none'; document.getElementById('2303.16046v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">8 pages, 6 figures, accepted for publication in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 673, A83 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.12192">arXiv:2303.12192</a> <span> [<a href="https://arxiv.org/pdf/2303.12192">pdf</a>, <a href="https://arxiv.org/format/2303.12192">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/acc653">10.3847/1538-4357/acc653 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observational Evidence of S-Web Source of the Slow Solar Wind </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Baker%2C+D">D. Baker</a>, <a href="/search/astro-ph?searchtype=author&query=Demoulin%2C+P">P. Demoulin</a>, <a href="/search/astro-ph?searchtype=author&query=Yardley%2C+S+L">S. L. Yardley</a>, <a href="/search/astro-ph?searchtype=author&query=Mihailescu%2C+T">T. Mihailescu</a>, <a href="/search/astro-ph?searchtype=author&query=van+Driel-Gesztelyi%2C+L">L. van Driel-Gesztelyi</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Amicis%2C+R">R. D'Amicis</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=To%2C+A+S+H">A. S. H. To</a>, <a href="/search/astro-ph?searchtype=author&query=Owen%2C+C+J">C. J. Owen</a>, <a href="/search/astro-ph?searchtype=author&query=Horbury%2C+T+S">T. S. Horbury</a>, <a href="/search/astro-ph?searchtype=author&query=Brooks%2C+D+H">D. H. Brooks</a>, <a href="/search/astro-ph?searchtype=author&query=Perrone%2C+D">D. Perrone</a>, <a href="/search/astro-ph?searchtype=author&query=French%2C+R+J">R. J. French</a>, <a href="/search/astro-ph?searchtype=author&query=James%2C+A+W">A. W. James</a>, <a href="/search/astro-ph?searchtype=author&query=Janvier%2C+M">M. Janvier</a>, <a href="/search/astro-ph?searchtype=author&query=Matthews%2C+S">S. Matthews</a>, <a href="/search/astro-ph?searchtype=author&query=Stangalini%2C+M">M. Stangalini</a>, <a href="/search/astro-ph?searchtype=author&query=Valori%2C+G">G. Valori</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P">P. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Anzar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Schuehle%2C+U">U. Schuehle</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a> , et al. (3 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.12192v1-abstract-short" style="display: inline;"> From 2022 March 18-21, active region (AR) 12967 was tracked simultaneously by Solar Orbiter (SO) at 0.35 au and Hinode/EIS at Earth. During this period, strong blue-shifted plasma upflows were observed along a thin, dark corridor of open field originating at the AR's leading polarity and continuing towards the southern extension of the northern polar coronal hole. A potential field source surface… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.12192v1-abstract-full').style.display = 'inline'; document.getElementById('2303.12192v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.12192v1-abstract-full" style="display: none;"> From 2022 March 18-21, active region (AR) 12967 was tracked simultaneously by Solar Orbiter (SO) at 0.35 au and Hinode/EIS at Earth. During this period, strong blue-shifted plasma upflows were observed along a thin, dark corridor of open field originating at the AR's leading polarity and continuing towards the southern extension of the northern polar coronal hole. A potential field source surface (PFSS) model shows large lateral expansion of the open magnetic field along the corridor. Squashing factor Q-maps of the large scale topology further confirm super-radial expansion in support of the S-Web theory for the slow wind. The thin corridor of upflows is identified as the source region of a slow solar wind stream characterised by approx. 300 km s-1 velocities, low proton temperatures of approx. 5 eV, extremely high density over 100 cm-3, and a short interval of moderate Alfvenicity accompanied by switchback events. When connectivity changes from the corridor to the eastern side of the AR, the in situ plasma parameters of the slow wind indicate a distinctly different source region. These observations provide strong evidence that the narrow open field corridors, forming part of the S-Web, produce extreme properties in their associated solar wind streams. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.12192v1-abstract-full').style.display = 'none'; document.getElementById('2303.12192v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.11001">arXiv:2303.11001</a> <span> [<a href="https://arxiv.org/pdf/2303.11001">pdf</a>, <a href="https://arxiv.org/format/2303.11001">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202345983">10.1051/0004-6361/202345983 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Slow solar wind sources. High-resolution observations with a quadrature view </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">Krzysztof Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">Louise Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">Conrad Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Janitzek%2C+N">Nils Janitzek</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">Fr茅d茅ric Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">Regina Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡ric Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">Emil Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">Sudip Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">Susanna Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">Hardi Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">Udo Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P">Phil Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">Luca Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">Cis Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.11001v1-abstract-short" style="display: inline;"> The origin of the slow solar wind is still an open issue. One possibility that has been suggested is that upflows at the edge of an active region can contribute to the slow solar wind. We aim to explain how the plasma upflows are generated, which mechanisms are responsible for them, and what the upflow region topology looks like. We investigated an upflow region using imaging data with the unp… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.11001v1-abstract-full').style.display = 'inline'; document.getElementById('2303.11001v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.11001v1-abstract-full" style="display: none;"> The origin of the slow solar wind is still an open issue. One possibility that has been suggested is that upflows at the edge of an active region can contribute to the slow solar wind. We aim to explain how the plasma upflows are generated, which mechanisms are responsible for them, and what the upflow region topology looks like. We investigated an upflow region using imaging data with the unprecedented temporal (3s) and spatial (2 pixels = 236km) resolution that were obtained on 30 March 2022 with the 174脜 of the Extreme-Ultraviolet Imager (EUI)/High Resolution Imager (HRI) on board Solar Orbiter. During this time, the EUI and Earth-orbiting satellites (Solar Dynamics Observatory, Hinode, and the Interface Region Imaging Spectrograph, IRIS) were located in quadrature (92 degrees), which provides a stereoscopic view with high resolution. We used the Hinode/EIS (Fe XII) spectroscopic data to find coronal upflow regions in the active region. The IRIS slit-jaw imager provides a high-resolution view of the transition region and chromosphere. For the first time, we have data that provide a quadrature view of a coronal upflow region with high spatial resolution. We found extended loops rooted in a coronal upflow region. Plasma upflows at the footpoints of extended loops determined spectroscopically through the Doppler shift are similar to the apparent upward motions seen through imaging in quadrature. The dynamics of small-scale structures in the upflow region can be used to identify two mechanisms of the plasma upflow: Mechanism I is reconnection of the hot coronal loops with open magnetic field lines in the solar corona, and mechanism II is reconnection of the small chromospheric loops with open magnetic field lines in the chromosphere or transition region. We identified the locations in which mechanisms I and II work. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.11001v1-abstract-full').style.display = 'none'; document.getElementById('2303.11001v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">10 pages, 6 figures, accepted for publication in A&A; manuscript is a part of Astronomy & Astrophysics special issue: Solar Orbiter First Results (Nominal Mission Phase)</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.05616">arXiv:2301.05616</a> <span> [<a href="https://arxiv.org/pdf/2301.05616">pdf</a>, <a href="https://arxiv.org/format/2301.05616">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202245586">10.1051/0004-6361/202245586 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First Perihelion of EUI on the Solar Orbiter mission </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">P. Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Huang%2C+Z">Z. Huang</a>, <a href="/search/astro-ph?searchtype=author&query=Janvier%2C+M">M. Janvier</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">M. Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Stegen%2C+K">K. Stegen</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">M. J. West</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a> , et al. (12 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.05616v1-abstract-short" style="display: inline;"> Context. The Extreme Ultraviolet Imager (EUI), onboard Solar Orbiter consists of three telescopes: the two High Resolution Imagers in EUV (HRIEUV) and in Lyman-伪 (HRILya), and the Full Sun Imager (FSI). Solar Orbiter/EUI started its Nominal Mission Phase on 2021 November 27. Aims. EUI images from the largest scales in the extended corona off limb, down to the smallest features at the base of the c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.05616v1-abstract-full').style.display = 'inline'; document.getElementById('2301.05616v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.05616v1-abstract-full" style="display: none;"> Context. The Extreme Ultraviolet Imager (EUI), onboard Solar Orbiter consists of three telescopes: the two High Resolution Imagers in EUV (HRIEUV) and in Lyman-伪 (HRILya), and the Full Sun Imager (FSI). Solar Orbiter/EUI started its Nominal Mission Phase on 2021 November 27. Aims. EUI images from the largest scales in the extended corona off limb, down to the smallest features at the base of the corona and chromosphere. EUI is therefore a key instrument for the connection science that is at the heart of the Solar Orbiter mission science goals. Methods. The highest resolution on the Sun is achieved when Solar Orbiter passes through the perihelion part of its orbit. On 2022 March 26, Solar Orbiter reached for the first time a distance to the Sun close to 0.3 au. No other coronal EUV imager has been this close to the Sun. Results. We review the EUI data sets obtained during the period 2022 March-April, when Solar Orbiter quickly moved from alignment with the Earth (2022 March 6), to perihelion (2022 March 26), to quadrature with the Earth (2022 March 29). We highlight the first observational results in these unique data sets and we report on the in-flight instrument performance. Conclusions. EUI has obtained the highest resolution images ever of the solar corona in the quiet Sun and polar coronal holes. Several active regions were imaged at unprecedented cadences and sequence durations. We identify in this paper a broad range of features that require deeper studies. Both FSI and HRIEUV operate at design specifications but HRILya suffered from performance issues near perihelion. We conclude emphasising the EUI open data policy and encouraging further detailed analysis of the events highlighted in this paper. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.05616v1-abstract-full').style.display = 'none'; document.getElementById('2301.05616v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 13 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 675, A110 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.02040">arXiv:2301.02040</a> <span> [<a href="https://arxiv.org/pdf/2301.02040">pdf</a>, <a href="https://arxiv.org/format/2301.02040">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244914">10.1051/0004-6361/202244914 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Temperature of Solar Orbiter/EUI quiet Sun small scale brightenings: evidence for a cooler component </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dolliou%2C+A">A. Dolliou</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Bocchialini%2C+K">K. Bocchialini</a>, <a href="/search/astro-ph?searchtype=author&query=Pelouze%2C+G">G. Pelouze</a>, <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">P. Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Stegen%2C+K">K. Stegen</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+E">E. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">M. Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.02040v2-abstract-short" style="display: inline;"> Context: On 2020 May 30, small and short-lived EUV brightenings were observed in the Quiet Sun (QS) during a four minutes sequence by EUI/HRIEUV on board Solar Orbiter. Their physical origin and possible impact on coronal or Transition Region (TR) heating are still to be determined. Aims: Our aim is to derive the statistical thermal evolution of these events in order to establish their coronal or… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.02040v2-abstract-full').style.display = 'inline'; document.getElementById('2301.02040v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.02040v2-abstract-full" style="display: none;"> Context: On 2020 May 30, small and short-lived EUV brightenings were observed in the Quiet Sun (QS) during a four minutes sequence by EUI/HRIEUV on board Solar Orbiter. Their physical origin and possible impact on coronal or Transition Region (TR) heating are still to be determined. Aims: Our aim is to derive the statistical thermal evolution of these events in order to establish their coronal or TR origin. Methods. Our thermal analysis takes advantage of the multithermal sensitivity of the Atmospheric Imaging Assembly (AIA) imager on board the Solar Dynamics Observatory (SDO). We first identified these HRIEUV events in the six coronal bands of AIA. We then performed a statistical time lag analysis, which quantifies the delays between the light curves from different bands. These time lags can give significant insights into the temperature evolution of these events. The analysis is performed taking into account the possible contribution to the results from the background and foreground emissions. Results: The events are characterized by time lags inferior to the AIA cadence of 12 s, for all nine couples of AIA bands analyzed. Our interpretation is the possible co-presence of events which reach or do not reach coronal temperatures ($\approx$ 1MK). We believe that the cool population dominates the events analyzed in this work. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.02040v2-abstract-full').style.display = 'none'; document.getElementById('2301.02040v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 24 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 8 figures, language and typo editing, accepted in A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 671, A64 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.02034">arXiv:2301.02034</a> <span> [<a href="https://arxiv.org/pdf/2301.02034">pdf</a>, <a href="https://arxiv.org/format/2301.02034">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/acb0c9">10.3847/1538-4357/acb0c9 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multi-stage reconnection powering a solar coronal jet </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">Lakshmi Pradeep Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Baker%2C+D">Deborah Baker</a>, <a href="/search/astro-ph?searchtype=author&query=Hannah%2C+I+G">Iain G. Hannah</a>, <a href="/search/astro-ph?searchtype=author&query=Ngampoopun%2C+N">Nawin Ngampoopun</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">Luca Teriaca</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.02034v1-abstract-short" style="display: inline;"> Coronal jets are short-lived eruptive features commonly observed in polar coronal holes and are thought to play a key role in the transfer of mass and energy into the solar corona. We describe unique contemporaneous observations of a coronal blowout jet seen by the Extreme Ultraviolet Imager onboard the Solar Orbiter spacecraft (SO/EUI) and the Atmospheric Imaging Assembly onboard the Solar Dynami… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.02034v1-abstract-full').style.display = 'inline'; document.getElementById('2301.02034v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.02034v1-abstract-full" style="display: none;"> Coronal jets are short-lived eruptive features commonly observed in polar coronal holes and are thought to play a key role in the transfer of mass and energy into the solar corona. We describe unique contemporaneous observations of a coronal blowout jet seen by the Extreme Ultraviolet Imager onboard the Solar Orbiter spacecraft (SO/EUI) and the Atmospheric Imaging Assembly onboard the Solar Dynamics Observatory (SDO/AIA). The coronal jet erupted from the south polar coronal hole, and was observed with high spatial and temporal resolution by both instruments. This enabled identification of the different stages of a breakout reconnection process producing the observed jet. We find bulk plasma flow kinematics of ~100-200 km/s across the lifetime of its observed propagation, with a distinct kink in the jet where it impacted and was subsequently guided by a nearby polar plume. We also identify a faint faster feature ahead of the bulk plasma motion propagating with a velocity of ~715 km/s which we attribute to untwisting of newly reconnected field lines during the eruption. A Differential Emission Measure (DEM) analysis using the SDO/AIA observations revealed a very weak jet signal, indicating that the erupting material was likely much cooler than the coronal passbands used to derive the DEM. This is consistent with the very bright appearance of the jet in the Lyman-$伪$ passband observed by SO/EUI. The DEM was used to estimate the radiative thermal energy of the source region of the coronal jet, finding a value of $\sim2\times10^{24}$ ergs, comparable to the energy of a nanoflare. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.02034v1-abstract-full').style.display = 'none'; document.getElementById('2301.02034v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 6 figures, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2212.05025">arXiv:2212.05025</a> <span> [<a href="https://arxiv.org/pdf/2212.05025">pdf</a>, <a href="https://arxiv.org/format/2212.05025">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202245431">10.1051/0004-6361/202245431 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Signatures of dynamic fibrils at the coronal base: Observations from Solar Orbiter/EUI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">Sudip Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">Hardi Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">Lakshmi Pradeep Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">Regina A. Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">Udo Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">Luca Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">Sami K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">Louise Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">Fr茅d茅ric Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">Susanna Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡ric Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">Cis Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">Emil Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">Conrad Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">Krzysztof Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Pelouze%2C+G">Gabriel Pelouze</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">Philip J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+W">Wei Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+M+C">Mark C. Cheung</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2212.05025v1-abstract-short" style="display: inline;"> The solar chromosphere hosts a wide variety of transients, including dynamic fibrils (DFs) that are characterised as elongated, jet-like features seen in active regions, often through H$伪$ diagnostics. So far, these features have been difficult to identify in coronal images primarily due to their small size and the lower spatial resolution of the current EUV imagers. Here we present the first unam… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.05025v1-abstract-full').style.display = 'inline'; document.getElementById('2212.05025v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2212.05025v1-abstract-full" style="display: none;"> The solar chromosphere hosts a wide variety of transients, including dynamic fibrils (DFs) that are characterised as elongated, jet-like features seen in active regions, often through H$伪$ diagnostics. So far, these features have been difficult to identify in coronal images primarily due to their small size and the lower spatial resolution of the current EUV imagers. Here we present the first unambiguous signatures of DFs in coronal EUV data using high-resolution images from the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter. Using the data acquired with the 174~脜 High Resolution Imager (HRI$_{EUV}$) of EUI, we find many bright dot-like features (of size 0.3-0.5 Mm) that move up and down (often repeatedly) in the core of an active region. In a space-time map, these features produce parabolic tracks akin to the chromospheric observations of DFs. Properties such as their speeds (14 km~s$^{-1}$), lifetime (332~s), deceleration (82 m~s$^{-2}$) and lengths (1293~km) are also reminiscent of the chromospheric DFs. The EUI data strongly suggest that these EUV bright dots are basically the hot tips (of the cooler chromospheric DFs) that could not be identified unambiguously before because of a lack of spatial resolution. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2212.05025v1-abstract-full').style.display = 'none'; document.getElementById('2212.05025v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 December, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A Letters. Event movie can be downloaded from https://drive.google.com/file/d/1o_4jHA5JbyQtrpUBtB3ItE_s3HjF6ncc/view?usp=sharing</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 670, L3 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.12203">arXiv:2209.12203</a> <span> [<a href="https://arxiv.org/pdf/2209.12203">pdf</a>, <a href="https://arxiv.org/format/2209.12203">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244170">10.1051/0004-6361/202244170 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Solar coronal heating from small-scale magnetic braids </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">H. Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">C. Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+W">W. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+M+C+M">M. C. M. Cheung</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.12203v3-abstract-short" style="display: inline;"> Relaxation of braided coronal magnetic fields through reconnection is thought to be a source of energy to heat plasma in active region coronal loops. However, observations of active region coronal heating associated with an untangling of magnetic braids remain sparse. One reason for this paucity could be the lack of coronal observations with a sufficiently high spatial and temporal resolution to c… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.12203v3-abstract-full').style.display = 'inline'; document.getElementById('2209.12203v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.12203v3-abstract-full" style="display: none;"> Relaxation of braided coronal magnetic fields through reconnection is thought to be a source of energy to heat plasma in active region coronal loops. However, observations of active region coronal heating associated with an untangling of magnetic braids remain sparse. One reason for this paucity could be the lack of coronal observations with a sufficiently high spatial and temporal resolution to capture this process in action. Using new observations with high spatial resolution (250-270 km on the Sun) and high cadence (3-10 s) from the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter, we observed the untangling of small-scale coronal braids in different active regions. The untangling is associated with impulsive heating of the gas in these braided loops. We assess that coronal magnetic braids overlying cooler chromospheric filamentary structures are perhaps more common. Furthermore, our observations show signatures of spatially coherent and intermittent coronal heating during the relaxation of the magnetic braids. Our study reveals the operation of gentle and impulsive modes of magnetic reconnection in the solar corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.12203v3-abstract-full').style.display = 'none'; document.getElementById('2209.12203v3-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Published in Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 667, A166 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.04251">arXiv:2209.04251</a> <span> [<a href="https://arxiv.org/pdf/2209.04251">pdf</a>, <a href="https://arxiv.org/format/2209.04251">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244403">10.1051/0004-6361/202244403 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> What drives decayless kink oscillations in active region coronal loops on the Sun? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">Sudip Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">Lakshmi P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">Patrick Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Peter%2C+H">Hardi Peter</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">Sami K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">Fr茅d茅ric Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">Luca Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">Regina A. Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">Udo Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">Susanna Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡ric Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">Louise Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">Cis Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">Emil Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">David M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Pelouze%2C+G">Gabriel Pelouze</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">Conrad Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">Krzysztof Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">Phil J. Smith</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2209.04251v1-abstract-short" style="display: inline;"> We study here the phenomena of decayless kink oscillations in a system of active region (AR) coronal loops. Using high resolution observations from two different instruments, namely the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we follow these AR loops for an hour each on three consecutive days. Our r… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.04251v1-abstract-full').style.display = 'inline'; document.getElementById('2209.04251v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.04251v1-abstract-full" style="display: none;"> We study here the phenomena of decayless kink oscillations in a system of active region (AR) coronal loops. Using high resolution observations from two different instruments, namely the Extreme Ultraviolet Imager (EUI) on board Solar Orbiter and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, we follow these AR loops for an hour each on three consecutive days. Our results show significantly more resolved decayless waves in the higher-resolution EUI data compared with the AIA data. Furthermore, the same system of loops exhibits many of these decayless oscillations on Day-2, while on Day-3, we detect very few oscillations and on Day-1, we find none at all. Analysis of photospheric magnetic field data reveals that at most times, these loops were rooted in sunspots, where supergranular flows are generally absent. This suggests that supergranular flows, which are often invoked as drivers of decayless waves, are not necessarily driving such oscillations in our observations. Similarly, our findings also cast doubt on other possible drivers of these waves, such as a transient driver or mode conversion of longitudinal waves near the loop footpoints. In conclusion, through our analysis we find that none of the commonly suspected sources proposed to drive decayless oscillations in active region loops seems to be operating in this event and hence, the search for that elusive wave driver needs to continue. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.04251v1-abstract-full').style.display = 'none'; document.getElementById('2209.04251v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 September, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted for publication in A&A Letters. Event movies can be downloaded from https://drive.google.com/drive/folders/1IFH17oBwJuz2U5zR4Ds_Y4oU5ZQCaVbR?usp=sharing</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 666, L2 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.04411">arXiv:2206.04411</a> <span> [<a href="https://arxiv.org/pdf/2206.04411">pdf</a>, <a href="https://arxiv.org/format/2206.04411">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s11207-022-02018-0">10.1007/s11207-022-02018-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Polarimetric Studies of a Fast Coronal Mass Ejection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">Marilena Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Inhester%2C+B">Bernd Inhester</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Shestov%2C+S+V">Sergei V. Shestov</a>, <a href="/search/astro-ph?searchtype=author&query=Bemporad%2C+A">Alessandro Bemporad</a>, <a href="/search/astro-ph?searchtype=author&query=Lamy%2C+P">Philippe Lamy</a>, <a href="/search/astro-ph?searchtype=author&query=Koutchmy%2C+S">Serge Koutchmy</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.04411v1-abstract-short" style="display: inline;"> In this work we performed a polarimetric study of a fast and wide coronal mass ejection (CME) observed on 12 July 2012 by the COR1 and COR2 instruments onboard Solar TErrestrial RElations Observatory (STEREO) mission. The CME source region was an X1.4 flare located at approximately S15W01 on the solar disk as observed from the Earth's perspective. The position of the CME as derived from the 3D Gra… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.04411v1-abstract-full').style.display = 'inline'; document.getElementById('2206.04411v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.04411v1-abstract-full" style="display: none;"> In this work we performed a polarimetric study of a fast and wide coronal mass ejection (CME) observed on 12 July 2012 by the COR1 and COR2 instruments onboard Solar TErrestrial RElations Observatory (STEREO) mission. The CME source region was an X1.4 flare located at approximately S15W01 on the solar disk as observed from the Earth's perspective. The position of the CME as derived from the 3D Graduated Cylindrical Shell (GCS) reconstruction method was at around S18W00 at 2.5 solar radii and S07W00 at 5.7 solar radii, meaning that the CME was deflected towards the Equator while propagating outward in the corona. The projected speed of the leading edge of the CME also evolved from around 200 km s$^{-1}$ in the lower corona to around 1000 km s$^{-1}$ in the COR2 field of view. The degree of polarisation of the CME is around 65 % but it can go as high as 80 % in some CME regions. The CME showed deviation of the polarisation angle from the tangential in the range of 10$^\circ$ - 15$^\circ$ (or more). Our analysis showed that this is mostly due to the fact that the sequence of three polarised images from where the polarised parameters are derived is not taken simultaneously, but at a difference of few seconds in time. In this interval of time, the CME is moving by at least two pixels in the FOV of the instruments and this displacement results in uncertainties in the polarisation parameters (degree of polarisation, polarisation angle, etc.). We propose some steps forward to improve the derivation of the polarisation. This study is important for analysing the future data from instruments with polarisation capabilities. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.04411v1-abstract-full').style.display = 'none'; document.getElementById('2206.04411v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.03090">arXiv:2206.03090</a> <span> [<a href="https://arxiv.org/pdf/2206.03090">pdf</a>, <a href="https://arxiv.org/format/2206.03090">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/ac8104">10.3847/2041-8213/ac8104 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Magnetic Switchback in the Solar Corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Telloni%2C+D">Daniele Telloni</a>, <a href="/search/astro-ph?searchtype=author&query=Zank%2C+G+P">Gary P. Zank</a>, <a href="/search/astro-ph?searchtype=author&query=Stangalini%2C+M">Marco Stangalini</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Liang%2C+H">Haoming Liang</a>, <a href="/search/astro-ph?searchtype=author&query=Nakanotani%2C+M">Masaru Nakanotani</a>, <a href="/search/astro-ph?searchtype=author&query=Andretta%2C+V">Vincenzo Andretta</a>, <a href="/search/astro-ph?searchtype=author&query=Antonucci%2C+E">Ester Antonucci</a>, <a href="/search/astro-ph?searchtype=author&query=Sorriso-Valvo%2C+L">Luca Sorriso-Valvo</a>, <a href="/search/astro-ph?searchtype=author&query=Adhikari%2C+L">Laxman Adhikari</a>, <a href="/search/astro-ph?searchtype=author&query=Zhao%2C+L">Lingling Zhao</a>, <a href="/search/astro-ph?searchtype=author&query=Marino%2C+R">Raffaele Marino</a>, <a href="/search/astro-ph?searchtype=author&query=Susino%2C+R">Roberto Susino</a>, <a href="/search/astro-ph?searchtype=author&query=Grimani%2C+C">Catia Grimani</a>, <a href="/search/astro-ph?searchtype=author&query=Fabi%2C+M">Michele Fabi</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Amicis%2C+R">Raffaella D'Amicis</a>, <a href="/search/astro-ph?searchtype=author&query=Perrone%2C+D">Denise Perrone</a>, <a href="/search/astro-ph?searchtype=author&query=Bruno%2C+R">Roberto Bruno</a>, <a href="/search/astro-ph?searchtype=author&query=Carbone%2C+F">Francesco Carbone</a>, <a href="/search/astro-ph?searchtype=author&query=Mancuso%2C+S">Salvatore Mancuso</a>, <a href="/search/astro-ph?searchtype=author&query=Romoli%2C+M">Marco Romoli</a>, <a href="/search/astro-ph?searchtype=author&query=Da+Deppo%2C+V">Vania Da Deppo</a>, <a href="/search/astro-ph?searchtype=author&query=Fineschi%2C+S">Silvano Fineschi</a>, <a href="/search/astro-ph?searchtype=author&query=Heinzel%2C+P">Petr Heinzel</a>, <a href="/search/astro-ph?searchtype=author&query=Moses%2C+J+D">John D. Moses</a> , et al. (27 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2206.03090v2-abstract-short" style="display: inline;"> Switchbacks are sudden, large radial deflections of the solar wind magnetic field, widely revealed in interplanetary space by the Parker Solar Probe. The switchbacks' formation mechanism and sources are still unresolved, although candidate mechanisms include Alfv茅nic turbulence, shear-driven Kelvin-Helmholtz instabilities, interchange reconnection, and geometrical effects related to the Parker spi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.03090v2-abstract-full').style.display = 'inline'; document.getElementById('2206.03090v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.03090v2-abstract-full" style="display: none;"> Switchbacks are sudden, large radial deflections of the solar wind magnetic field, widely revealed in interplanetary space by the Parker Solar Probe. The switchbacks' formation mechanism and sources are still unresolved, although candidate mechanisms include Alfv茅nic turbulence, shear-driven Kelvin-Helmholtz instabilities, interchange reconnection, and geometrical effects related to the Parker spiral. This Letter presents observations from the Metis coronagraph onboard Solar Orbiter of a single large propagating S-shaped vortex, interpreted as first evidence of a switchback in the solar corona. It originated above an active region with the related loop system bounded by open-field regions to the East and West. Observations, modeling, and theory provide strong arguments in favor of the interchange reconnection origin of switchbacks. Metis measurements suggest that the initiation of the switchback may also be an indicator of the origin of slow solar wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.03090v2-abstract-full').style.display = 'none'; document.getElementById('2206.03090v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2022. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.15214">arXiv:2205.15214</a> <span> [<a href="https://arxiv.org/pdf/2205.15214">pdf</a>, <a href="https://arxiv.org/format/2205.15214">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202244020">10.1051/0004-6361/202244020 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Prominence eruption observed in He II 304 脜 up to $>6 R_\sun$ by EUI/FSI aboard Solar Orbiter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">M. Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Auchere%2C+F">F. Auchere</a>, <a href="/search/astro-ph?searchtype=author&query=Heinzel%2C+P">P. Heinzel</a>, <a href="/search/astro-ph?searchtype=author&query=Seaton%2C+D+B">D. B. Seaton</a>, <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">E. Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Jejcic%2C+S">S. Jejcic</a>, <a href="/search/astro-ph?searchtype=author&query=Janssens%2C+J">J. Janssens</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Nicula%2C+B">B. Nicula</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Hayes%2C+L+A">L. A. Hayes</a>, <a href="/search/astro-ph?searchtype=author&query=Jebaraj%2C+I+C">I. C. Jebaraj</a>, <a href="/search/astro-ph?searchtype=author&query=Talpeanu%2C+D+-">D. -C. Talpeanu</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Huys%2C+E">E. D'Huys</a>, <a href="/search/astro-ph?searchtype=author&query=Dolla%2C+L">L. Dolla</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Magdalenic%2C+J">J. Magdalenic</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Shestov%2C+S">S. Shestov</a>, <a href="/search/astro-ph?searchtype=author&query=Stegen%2C+K">K. Stegen</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Sasso%2C+C">C. Sasso</a> , et al. (2 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2205.15214v1-abstract-short" style="display: inline;"> We report observations of a unique, large prominence eruption that was observed in the He II 304 脜 passband of the the Extreme Ultraviolet Imager/Full Sun Imager telescope aboard Solar Orbiter on 15-16 February 2022. Observations from several vantage points (Solar Orbiter, the Solar-Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and Earth-orbiting satellites) were used… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.15214v1-abstract-full').style.display = 'inline'; document.getElementById('2205.15214v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.15214v1-abstract-full" style="display: none;"> We report observations of a unique, large prominence eruption that was observed in the He II 304 脜 passband of the the Extreme Ultraviolet Imager/Full Sun Imager telescope aboard Solar Orbiter on 15-16 February 2022. Observations from several vantage points (Solar Orbiter, the Solar-Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and Earth-orbiting satellites) were used to measure the kinematics of the erupting prominence and the associated coronal mass ejection. Three-dimensional reconstruction was used to calculate the deprojected positions and speeds of different parts of the prominence. Observations in several passbands allowed us to analyse the radiative properties of the erupting prominence. The leading parts of the erupting prominence and the leading edge of the corresponding coronal mass ejection propagate at speeds of around 1700 km/s and 2200 km/s, respectively, while the trailing parts of the prominence are significantly slower (around 500 km/s). Parts of the prominence are tracked up to heights of over $6 R_\sun$. The He II emission is probably produced via collisional excitation rather than scattering. Surprisingly, the brightness of a trailing feature increases with height. The reported prominence is the first observed in He II 304 脜 emission at such a great height (above 6 $R_\sun$). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.15214v1-abstract-full').style.display = 'none'; document.getElementById('2205.15214v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 662, L5 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.02338">arXiv:2205.02338</a> <span> [<a href="https://arxiv.org/pdf/2205.02338">pdf</a>, <a href="https://arxiv.org/format/2205.02338">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac66e4">10.3847/1538-4357/ac66e4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Mixing the solar wind proton and electron scales. Theory and 2D-PIC simulations of firehose instability </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez%2C+R+A">R. A. L贸pez</a>, <a href="/search/astro-ph?searchtype=author&query=Micera%2C+A">A. Micera</a>, <a href="/search/astro-ph?searchtype=author&query=Lazar%2C+M">M. Lazar</a>, <a href="/search/astro-ph?searchtype=author&query=Poedts%2C+S">S. Poedts</a>, <a href="/search/astro-ph?searchtype=author&query=Lapenta%2C+G">G. Lapenta</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Boella%2C+E">E. Boella</a>, <a href="/search/astro-ph?searchtype=author&query=Shaaban%2C+S+M">S. M. Shaaban</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2205.02338v1-abstract-short" style="display: inline;"> Firehose-like instabilities (FIs) are cited in multiple astrophysical applications. Of particular interest are the kinetic manifestations in weakly-collisional or even collisionless plasmas, where these instabilities are expected to contribute to the evolution of macroscopic parameters. Relatively recent studies have initiated a realistic description of FIs, as induced by the interplay of both spe… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.02338v1-abstract-full').style.display = 'inline'; document.getElementById('2205.02338v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.02338v1-abstract-full" style="display: none;"> Firehose-like instabilities (FIs) are cited in multiple astrophysical applications. Of particular interest are the kinetic manifestations in weakly-collisional or even collisionless plasmas, where these instabilities are expected to contribute to the evolution of macroscopic parameters. Relatively recent studies have initiated a realistic description of FIs, as induced by the interplay of both species, electrons and protons, dominant in the solar wind plasma. This work complements the current knowledge with new insights from linear theory and the first disclosures from 2D PIC simulations, identifying the fastest growing modes near the instability thresholds and their long-run consequences on the anisotropic distributions. Thus, unlike previous setups, these conditions are favorable to those aperiodic branches that propagate obliquely to the uniform magnetic field, with (maximum) growth rates higher than periodic, quasi-parallel modes. Theoretical predictions are, in general, confirmed by the simulations. The aperiodic electron FI (a-EFI) remains unaffected by the proton anisotropy, and saturates rapidly at low-level fluctuations. Regarding the firehose instability at proton scales, we see a stronger competition between the periodic and aperiodic branches. For the parameters chosen in our analysis, the a-PFI is excited before than the p-PFI, with the latter reaching a significantly higher fluctuation power. However, both branches are significantly enhanced by the presence of anisotropic electrons. The interplay between EFIs and PFIs also produces a more pronounced proton isotropization. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.02338v1-abstract-full').style.display = 'none'; document.getElementById('2205.02338v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Accepted in ApJ</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.04027">arXiv:2204.04027</a> <span> [<a href="https://arxiv.org/pdf/2204.04027">pdf</a>, <a href="https://arxiv.org/ps/2204.04027">ps</a>, <a href="https://arxiv.org/format/2204.04027">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202243257">10.1051/0004-6361/202243257 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Automatic detection of small-scale EUV brightenings observed by the Solar Orbiter/EUI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Alipour%2C+N">N. Alipour</a>, <a href="/search/astro-ph?searchtype=author&query=Safari%2C+H">H. Safari</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Chitta%2C+L+P">L. P. Chitta</a>, <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">P. Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Dolla%2C+L">L. Dolla</a>, <a href="/search/astro-ph?searchtype=author&query=Georgoulis%2C+M+K">M. K. Georgoulis</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Katsiyannis%2C+A+C">A. C. Katsiyannis</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Mandal%2C+S">S. Mandal</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Podladchikova%2C+O">O. Podladchikova</a>, <a href="/search/astro-ph?searchtype=author&query=Petrova%2C+E">E. Petrova</a>, <a href="/search/astro-ph?searchtype=author&query=Soubri%C3%A9%2C+%C3%89">脡. Soubri茅</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Schwanitz%2C+C">C. Schwanitz</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">M. J. West</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2204.04027v1-abstract-short" style="display: inline;"> Context. Accurate detections of frequent small-scale extreme ultraviolet (EUV) brightenings are essential to the investigation of the physical processes heating the corona. Aims. We detected small-scale brightenings, termed campfires, using their morphological and intensity structures as observed in coronal EUV imaging observations for statistical analysis. Methods. We applied a method based on Ze… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.04027v1-abstract-full').style.display = 'inline'; document.getElementById('2204.04027v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.04027v1-abstract-full" style="display: none;"> Context. Accurate detections of frequent small-scale extreme ultraviolet (EUV) brightenings are essential to the investigation of the physical processes heating the corona. Aims. We detected small-scale brightenings, termed campfires, using their morphological and intensity structures as observed in coronal EUV imaging observations for statistical analysis. Methods. We applied a method based on Zernike moments and a support vector machine classifier to automatically identify and track campfires observed by Solar Orbiter/Extreme Ultraviolet Imager (EUI) and SDO/AIA. Results. This method detected 8678 campfires (with length scales between 400 km and 4000 km) from a sequence of 50 High Resolution EUV telescope (HRIEUV) 174脜 images. From 21 near co-temporal AIA images covering the same field of view as EUI, we found 1131 campfires, 58% of which were also detected in HRIEUV images. In contrast, about 16% of campfires recognized in HRIEUV were detected by AIA. We obtain a campfire birthrate of 2*10-16m-2s-1. About 40% of campfires show a duration longer than 5 s, having been observed in at least two HRIEUV images. We find that 27% of campfires were found in coronal bright points and the remaining 73% have occurred out of coronal bright points. We detected 23 EUI campfires with a duration greater than 245 s. We found that about 80% of campfires are formed at supergranular boundaries, and the features with the highest total intensities are generated at network junctions and intense H I Lyman-伪 emission regions observed by EUI/HRILya. The probability distribution functions for the total intensity, peak intensity, and projected area of campfires follow a power law behavior with absolute indices between 2 and 3. This self-similar behavior is a possible signature of self-organization, or even self-organized criticality, in the campfire formation process. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.04027v1-abstract-full').style.display = 'none'; document.getElementById('2204.04027v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 8 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 663, A128 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.08643">arXiv:2203.08643</a> <span> [<a href="https://arxiv.org/pdf/2203.08643">pdf</a>, <a href="https://arxiv.org/format/2203.08643">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202142362">10.1051/0004-6361/202142362 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Initiation of Alfv茅nic turbulence by Alfven wave collisions: A numerical study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Shestov%2C+S+V">S. V. Shestov</a>, <a href="/search/astro-ph?searchtype=author&query=Voitenko%2C+Y+M">Y. M. Voitenko</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2203.08643v1-abstract-short" style="display: inline;"> In the framework of compressional magnetohydrodynamics (MHD), we numerically studied the commonly accepted presumption that the Alfv茅nic turbulence is generated by the collisions between counter-propagating Alfv茅n waves (AWs). In the conditions typical for the low-beta solar corona and inner solar wind, we launched two counter-propagating AWs in the three-dimensional simulation box and analyzed po… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.08643v1-abstract-full').style.display = 'inline'; document.getElementById('2203.08643v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.08643v1-abstract-full" style="display: none;"> In the framework of compressional magnetohydrodynamics (MHD), we numerically studied the commonly accepted presumption that the Alfv茅nic turbulence is generated by the collisions between counter-propagating Alfv茅n waves (AWs). In the conditions typical for the low-beta solar corona and inner solar wind, we launched two counter-propagating AWs in the three-dimensional simulation box and analyzed polarization and spectral properties of perturbations generated before and after AW collisions. The observed post-collisional perturbations have different polarizations and smaller cross-field scales than the original waves, which supports theoretical scenarios with direct turbulent cascades. However, contrary to theoretical expectations, the spectral transport is strongly suppressed at the scales satisfying the classic critical balance of incompressional MHD. Instead, a modified critical balance can be established by colliding AWs with significantly shorter perpendicular scales. We discuss consequences of these effects for the turbulence dynamics and turbulent heating of compressional plasmas. In particular, solar coronal loops can be heated by the strong turbulent cascade if the characteristic widths of the loop substructures are more than ten times smaller than the loop width. The revealed new properties of AW collisions have to be incorporated in the theoretical models of AW turbulence and related applications. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.08643v1-abstract-full').style.display = 'none'; document.getElementById('2203.08643v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 16 March, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">9 pages, 9 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 661, A93 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.10294">arXiv:2202.10294</a> <span> [<a href="https://arxiv.org/pdf/2202.10294">pdf</a>, <a href="https://arxiv.org/format/2202.10294">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202243162">10.1051/0004-6361/202243162 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Coronal Mass Ejection followed by a prominence eruption and a plasma blob as observed by Solar Orbiter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bemporad%2C+A">A. Bemporad</a>, <a href="/search/astro-ph?searchtype=author&query=Andretta%2C+V">V. Andretta</a>, <a href="/search/astro-ph?searchtype=author&query=Susino%2C+R">R. Susino</a>, <a href="/search/astro-ph?searchtype=author&query=Mancuso%2C+S">S. Mancuso</a>, <a href="/search/astro-ph?searchtype=author&query=Spadaro%2C+D">D. Spadaro</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">M. Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=D%27Huys%2C+E">E. D'Huys</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Talpeanu%2C+D+-">D. -C. Talpeanu</a>, <a href="/search/astro-ph?searchtype=author&query=Colaninno%2C+R">R. Colaninno</a>, <a href="/search/astro-ph?searchtype=author&query=Hess%2C+P">P. Hess</a>, <a href="/search/astro-ph?searchtype=author&query=Koza%2C+J">J. Koza</a>, <a href="/search/astro-ph?searchtype=author&query=Jejcic%2C+S">S. Jejcic</a>, <a href="/search/astro-ph?searchtype=author&query=Heinzel%2C+P">P. Heinzel</a>, <a href="/search/astro-ph?searchtype=author&query=Antonucci%2C+E">E. Antonucci</a>, <a href="/search/astro-ph?searchtype=author&query=Da+Deppo%2C+V">V. Da Deppo</a>, <a href="/search/astro-ph?searchtype=author&query=Fineschi%2C+S">S. Fineschi</a>, <a href="/search/astro-ph?searchtype=author&query=Frassati%2C+F">F. Frassati</a>, <a href="/search/astro-ph?searchtype=author&query=Jerse%2C+G">G. Jerse</a>, <a href="/search/astro-ph?searchtype=author&query=Landini%2C+F">F. Landini</a>, <a href="/search/astro-ph?searchtype=author&query=Naletto%2C+G">G. Naletto</a>, <a href="/search/astro-ph?searchtype=author&query=Nicolini%2C+G">G. Nicolini</a>, <a href="/search/astro-ph?searchtype=author&query=Pancrazzi%2C+M">M. Pancrazzi</a>, <a href="/search/astro-ph?searchtype=author&query=Romoli%2C+M">M. Romoli</a> , et al. (4 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2202.10294v1-abstract-short" style="display: inline;"> On February 12, 2021 two subsequent eruptions occurred above the West limb, as seen along the Sun-Earth line. The first event was a typical slow Coronal Mass Ejection (CME), followed $\sim 7$ hours later by a smaller and collimated prominence eruption, originating Southward with respect to the CME, followed by a plasma blob. These events were observed not only by SOHO and STEREO-A missions, but al… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.10294v1-abstract-full').style.display = 'inline'; document.getElementById('2202.10294v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.10294v1-abstract-full" style="display: none;"> On February 12, 2021 two subsequent eruptions occurred above the West limb, as seen along the Sun-Earth line. The first event was a typical slow Coronal Mass Ejection (CME), followed $\sim 7$ hours later by a smaller and collimated prominence eruption, originating Southward with respect to the CME, followed by a plasma blob. These events were observed not only by SOHO and STEREO-A missions, but also by the suite of remote sensing instruments on-board Solar Orbiter (SolO). This work shows how data acquired by the Full Sun Imager (FSI), Metis coronagraph, and Heliospheric Imager (SoloHI) from the SolO perspective can be combined to study the eruptions and the different source regions. Moreover, we show how Metis data can be analyzed to provide new information about solar eruptions. Different 3D reconstruction methods were applied to the data acquired by different spacecraft including remote sensing instruments on-board SolO. Images acquired by both Metis channels in the Visible Light (VL) and H I Lyman$-伪$ line (UV) were combined to derive physical information on the expanding plasma. The polarization ratio technique was also applied for the first time to the Metis images acquired in the VL channel. The two eruptions were followed in 3D from their source region to their expansion in the intermediate corona. Thanks to the combination of VL and UV Metis data, the formation of a post-CME Current Sheet (CS) was followed for the first time in the intermediate corona. The plasma temperature gradient across a post-CME blob propagating along the CS was also measured for the first time. Application of the polarization ratio technique to Metis data shows that, thanks to the combination of four different polarization measurements, the errors are reduced by $\sim 5-7$\%, thus better constraining the 3D distribution of plasma. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.10294v1-abstract-full').style.display = 'none'; document.getElementById('2202.10294v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 21 February, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">15 pages, 14 figures, accepted for publication on A&A</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 665, A7 (2022) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.08408">arXiv:2110.08408</a> <span> [<a href="https://arxiv.org/pdf/2110.08408">pdf</a>, <a href="https://arxiv.org/format/2110.08408">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s11214-021-00857-0">10.1007/s11214-021-00857-0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Understanding the Origins of Problem Geomagnetic Storms Associated With "Stealth" Coronal Mass Ejections </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nitta%2C+N+V">Nariaki V. Nitta</a>, <a href="/search/astro-ph?searchtype=author&query=Mulligan%2C+T">Tamitha Mulligan</a>, <a href="/search/astro-ph?searchtype=author&query=Kilpua%2C+E+K+J">Emilia K. J. Kilpua</a>, <a href="/search/astro-ph?searchtype=author&query=Lynch%2C+B+J">Benjamin J. Lynch</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">Marilena Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Kane%2C+J">Jennifer O'Kane</a>, <a href="/search/astro-ph?searchtype=author&query=Pagano%2C+P">Paolo Pagano</a>, <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Pomoell%2C+J">Jens Pomoell</a>, <a href="/search/astro-ph?searchtype=author&query=Richardson%2C+I+G">Ian G. Richardson</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Rouillard%2C+A+P">Alexis P. Rouillard</a>, <a href="/search/astro-ph?searchtype=author&query=Sinha%2C+S">Suvadip Sinha</a>, <a href="/search/astro-ph?searchtype=author&query=Srivastava%2C+N">Nandita Srivastava</a>, <a href="/search/astro-ph?searchtype=author&query=Talpeanu%2C+D">Dana-Camelia Talpeanu</a>, <a href="/search/astro-ph?searchtype=author&query=Yardley%2C+S+L">Stephanie L. Yardley</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.08408v1-abstract-short" style="display: inline;"> Geomagnetic storms are an important aspect of space weather and can result in significant impacts on space- and ground-based assets. The majority of strong storms are associated with the passage of interplanetary coronal mass ejections (ICMEs) in the near-Earth environment. In many cases, these ICMEs can be traced back unambiguously to a specific coronal mass ejection (CME) and solar activity on t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.08408v1-abstract-full').style.display = 'inline'; document.getElementById('2110.08408v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.08408v1-abstract-full" style="display: none;"> Geomagnetic storms are an important aspect of space weather and can result in significant impacts on space- and ground-based assets. The majority of strong storms are associated with the passage of interplanetary coronal mass ejections (ICMEs) in the near-Earth environment. In many cases, these ICMEs can be traced back unambiguously to a specific coronal mass ejection (CME) and solar activity on the frontside of the Sun. Hence, predicting the arrival of ICMEs at Earth from routine observations of CMEs and solar activity currently makes a major contribution to the forecasting of geomagnetic storms. However, it is clear that some ICMEs, which may also cause enhanced geomagnetic activity, cannot be traced back to an observed CME, or, if the CME is identified, its origin may be elusive or ambiguous in coronal images. Such CMEs have been termed "stealth CMEs." In this review, we focus on these "problem" geomagnetic storms in the sense that the solar/CME precursors are enigmatic and stealthy. We start by reviewing evidence for stealth CMEs discussed in past studies. We then identify several moderate to strong geomagnetic storms (minimum Dst < -50 nT) in solar cycle 24 for which the related solar sources and/or CMEs are unclear and apparently stealthy. We discuss the solar and in situ circumstances of these events and identify several scenarios that may account for their elusive solar signatures. These range from observational limitations (e.g., a coronagraph near Earth may not detect an incoming CME if it is diffuse and not wide enough) to the possibility that there is a class of mass ejections from the Sun that have only weak or hard-to-observe coronal signatures. In particular, some of these sources are only clearly revealed by considering the evolution of coronal structures over longer time intervals than is usually considered. We also review a variety of numerical modelling approaches... <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.08408v1-abstract-full').style.display = 'none'; document.getElementById('2110.08408v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">60 pages, 25 figures, 5 tables. Accepted for publication in Space Science Reviews</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Space Sci Rev 217, 82 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2110.02190">arXiv:2110.02190</a> <span> [<a href="https://arxiv.org/pdf/2110.02190">pdf</a>, <a href="https://arxiv.org/format/2110.02190">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2021JA029770">10.1029/2021JA029770 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic Structure and Propagation of Two Interacting CMEs from the Sun to Saturn </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Nieves-Chinchilla%2C+T">Teresa Nieves-Chinchilla</a>, <a href="/search/astro-ph?searchtype=author&query=Kilpua%2C+E+K+J">Emilia K. J. Kilpua</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+D">David Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Jian%2C+L+K">Lan K. Jian</a>, <a href="/search/astro-ph?searchtype=author&query=Witasse%2C+O">Olivier Witasse</a>, <a href="/search/astro-ph?searchtype=author&query=Provan%2C+G">Gabrielle Provan</a>, <a href="/search/astro-ph?searchtype=author&query=Tao%2C+C">Chihiro Tao</a>, <a href="/search/astro-ph?searchtype=author&query=Lamy%2C+L">Laurent Lamy</a>, <a href="/search/astro-ph?searchtype=author&query=Bradley%2C+T+J">Thomas J. Bradley</a>, <a href="/search/astro-ph?searchtype=author&query=Mays%2C+M+L">M. Leila Mays</a>, <a href="/search/astro-ph?searchtype=author&query=M%C3%B6stl%2C+C">Christian M枚stl</a>, <a href="/search/astro-ph?searchtype=author&query=Roussos%2C+E">Elias Roussos</a>, <a href="/search/astro-ph?searchtype=author&query=Futaana%2C+Y">Yoshifumi Futaana</a>, <a href="/search/astro-ph?searchtype=author&query=Masters%2C+A">Adam Masters</a>, <a href="/search/astro-ph?searchtype=author&query=S%C3%A1nchez-Cano%2C+B">Beatriz S谩nchez-Cano</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2110.02190v1-abstract-short" style="display: inline;"> One of the grand challenges in heliophysics is the characterisation of coronal mass ejection (CME) magnetic structure and evolution from eruption at the Sun through heliospheric propagation. At present, the main difficulties are related to the lack of direct measurements of the coronal magnetic fields and the lack of 3D in-situ measurements of the CME body in interplanetary space. Nevertheless, th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.02190v1-abstract-full').style.display = 'inline'; document.getElementById('2110.02190v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2110.02190v1-abstract-full" style="display: none;"> One of the grand challenges in heliophysics is the characterisation of coronal mass ejection (CME) magnetic structure and evolution from eruption at the Sun through heliospheric propagation. At present, the main difficulties are related to the lack of direct measurements of the coronal magnetic fields and the lack of 3D in-situ measurements of the CME body in interplanetary space. Nevertheless, the evolution of a CME magnetic structure can be followed using a combination of multi-point remote-sensing observations and multi-spacecraft in-situ measurements as well as modelling. Accordingly, we present in this work the analysis of two CMEs that erupted from the Sun on 28 April 2012. We follow their eruption and early evolution using remote-sensing data, finding indications of CME--CME interaction, and then analyse their interplanetary counterpart(s) using in-situ measurements at Venus, Earth, and Saturn. We observe a seemingly single flux rope at all locations, but find possible signatures of interaction at Earth, where high-cadence plasma data are available. Reconstructions of the in-situ flux ropes provide almost identical results at Venus and Earth but show greater discrepancies at Saturn, suggesting that the CME was highly distorted and/or that further interaction with nearby solar wind structures took place before 10 AU. This work highlights the difficulties in connecting structures from the Sun to the outer heliosphere and demonstrates the importance of multi-spacecraft studies to achieve a deeper understanding of the magnetic configuration of CMEs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2110.02190v1-abstract-full').style.display = 'none'; document.getElementById('2110.02190v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 October, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">40 pages, 11 figures, accepted for publication in Journal of Geophysical Research: Space Physics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2109.02169">arXiv:2109.02169</a> <span> [<a href="https://arxiv.org/pdf/2109.02169">pdf</a>, <a href="https://arxiv.org/format/2109.02169">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202141010">10.1051/0004-6361/202141010 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Stereoscopy of extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">M. Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Auch%C3%A8re%2C+F">F. Auch猫re</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Soubri%C3%A9%2C+E">E. Soubri茅</a>, <a href="/search/astro-ph?searchtype=author&query=Thompson%2C+W+T">W. T. Thompson</a>, <a href="/search/astro-ph?searchtype=author&query=Inhester%2C+B">B. Inhester</a>, <a href="/search/astro-ph?searchtype=author&query=Nicula%2C+B">B. Nicula</a>, <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">P. Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+S">S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+%C3%89">脡. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Barczynski%2C+K">K. Barczynski</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Stegen%2C+K">K. Stegen</a>, <a href="/search/astro-ph?searchtype=author&query=Dolla%2C+L">L. Dolla</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">L. Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Sch%C3%BChle%2C+U">U. Sch眉hle</a>, <a href="/search/astro-ph?searchtype=author&query=Podladchikova%2C+O">O. Podladchikova</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Haberreiter%2C+M">M. Haberreiter</a> , et al. (5 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2109.02169v1-abstract-short" style="display: inline;"> The 3D fine structure of the solar atmosphere is still not fully understood as most of the available observations are taken from a single vantage point. The goal of the paper is to study the 3D distribution of small-scale brightening events ("campfires") discovered in the EUV quiet Sun by the Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter. We used a first commissioning data set acquired by… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.02169v1-abstract-full').style.display = 'inline'; document.getElementById('2109.02169v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2109.02169v1-abstract-full" style="display: none;"> The 3D fine structure of the solar atmosphere is still not fully understood as most of the available observations are taken from a single vantage point. The goal of the paper is to study the 3D distribution of small-scale brightening events ("campfires") discovered in the EUV quiet Sun by the Extreme Ultraviolet Imager (EUI) aboard Solar Orbiter. We used a first commissioning data set acquired by the EUI's High Resolution EUV telescope on 30 May 2020 in the 174 脜 passband and we combined it with simultaneous data taken by the Atmospheric Imaging Assembly (AIA) aboard the Solar Dynamics Observatory in a similar 171 脜 passband. The two-pixel spatial resolution of the two telescopes is 400 km and 880 km, respectively, which is sufficient to identify the campfires in both data sets. The two spacecraft had an angular separation of around 31.5 degrees (essentially in heliographic longitude), which allowed for the 3D reconstruction of the campfire position. These observations represent the first time that stereoscopy was achieved for brightenings at such a small scale. Manual and automatic triangulation methods were used to characterize the campfire data. The height of the campfires is located between 1000 km and 5000 km above the photosphere and we find a good agreement between the manual and automatic methods. The internal structure of campfires is mostly unresolved by AIA; however, for a particularly large campfire, we were able to triangulate a few pixels, which are all in a narrow range between 2500 and 4500 km. The low height of EUI campfires suggests that they belong to the previously unresolved fine structure of the transition region and low corona of the quiet Sun. They are probably apexes of small-scale dynamic loops heated internally to coronal temperatures. This work demonstrates that high-resolution stereoscopy of structures in the solar atmosphere has become feasible. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2109.02169v1-abstract-full').style.display = 'none'; document.getElementById('2109.02169v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 5 September, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 656, A35 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.15975">arXiv:2106.15975</a> <span> [<a href="https://arxiv.org/pdf/2106.15975">pdf</a>, <a href="https://arxiv.org/format/2106.15975">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ac1067">10.3847/1538-4357/ac1067 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the role of solar wind expansion as a source of whistler waves: scattering of suprathermal electrons and heat flux regulation in the inner heliosphere </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Micera%2C+A">A. Micera</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez%2C+R+A">R. A. L贸pez</a>, <a href="/search/astro-ph?searchtype=author&query=Boella%2C+E">E. Boella</a>, <a href="/search/astro-ph?searchtype=author&query=Tenerani%2C+A">A. Tenerani</a>, <a href="/search/astro-ph?searchtype=author&query=Velli%2C+M">M. Velli</a>, <a href="/search/astro-ph?searchtype=author&query=Lapenta%2C+G">G. Lapenta</a>, <a href="/search/astro-ph?searchtype=author&query=Innocenti%2C+M+E">M. E. Innocenti</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.15975v2-abstract-short" style="display: inline;"> The role of solar wind expansion in generating whistler waves is investigated using the EB-iPic3D code, which models solar wind expansion self-consistently within a fully kinetic semi-implicit approach. The simulation is initialized with an electron velocity distribution function modeled after Parker Solar Probe observations during its first perihelion at 0.166 au, consisting of a dense core and a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.15975v2-abstract-full').style.display = 'inline'; document.getElementById('2106.15975v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.15975v2-abstract-full" style="display: none;"> The role of solar wind expansion in generating whistler waves is investigated using the EB-iPic3D code, which models solar wind expansion self-consistently within a fully kinetic semi-implicit approach. The simulation is initialized with an electron velocity distribution function modeled after Parker Solar Probe observations during its first perihelion at 0.166 au, consisting of a dense core and an anti-sunward strahl. This distribution function is initially stable with respect to kinetic instabilities. Expansion drives the solar wind into successive regimes where whistler heat flux instabilities are triggered. These instabilities produce sunward whistler waves initially characterized by predominantly oblique propagation with respect to the interplanetary magnetic field. The excited waves interact with the electrons via resonant scattering processes. As a consequence, the strahl pitch angle distribution broadens and its drift velocity reduces. Strahl electrons are scattered in the direction perpendicular to the magnetic field, and an electron halo is formed. At a later stage, resonant electron firehose instability is triggered and further affects the electron temperature anisotropy as the solar wind expands. Wave-particle interaction processes are accompanied by a substantial reduction of the solar wind heat flux. The simulated whistler waves are in qualitative agreement with observations in terms of wave frequencies, amplitudes and propagation angles. Our work proposes an explanation for the observations of oblique and parallel whistler waves in the solar wind. We conclude that solar wind expansion has to be factored in when trying to explain kinetic processes at different heliocentric distances. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.15975v2-abstract-full').style.display = 'none'; document.getElementById('2106.15975v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 July, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 30 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.07571">arXiv:2106.07571</a> <span> [<a href="https://arxiv.org/pdf/2106.07571">pdf</a>, <a href="https://arxiv.org/format/2106.07571">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3389/fspas.2021.695966">10.3389/fspas.2021.695966 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Investigating Remote-sensing Techniques to Reveal Stealth Coronal Mass Ejections </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Nitta%2C+N+V">Nariaki V. Nitta</a>, <a href="/search/astro-ph?searchtype=author&query=Mulligan%2C+T">Tamitha Mulligan</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">Marilena Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Kane%2C+J">Jennifer O'Kane</a>, <a href="/search/astro-ph?searchtype=author&query=Richardson%2C+I+G">Ian G. Richardson</a>, <a href="/search/astro-ph?searchtype=author&query=Sinha%2C+S">Suvadip Sinha</a>, <a href="/search/astro-ph?searchtype=author&query=Srivastava%2C+N">Nandita Srivastava</a>, <a href="/search/astro-ph?searchtype=author&query=Yardley%2C+S+L">Stephanie L. Yardley</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2106.07571v1-abstract-short" style="display: inline;"> Eruptions of coronal mass ejections (CMEs) from the Sun are usually associated with a number of signatures that can be identified in solar disc imagery. However, there are cases in which a CME that is well observed in coronagraph data is missing a clear low-coronal counterpart. These events have received attention during recent years, mainly as a result of the increased availability of multi-point… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.07571v1-abstract-full').style.display = 'inline'; document.getElementById('2106.07571v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.07571v1-abstract-full" style="display: none;"> Eruptions of coronal mass ejections (CMEs) from the Sun are usually associated with a number of signatures that can be identified in solar disc imagery. However, there are cases in which a CME that is well observed in coronagraph data is missing a clear low-coronal counterpart. These events have received attention during recent years, mainly as a result of the increased availability of multi-point observations, and are now known as 'stealth CMEs'. In this work, we analyse examples of stealth CMEs featuring various levels of ambiguity. All the selected case studies produced a large-scale CME detected by coronagraphs and were observed from at least one secondary viewpoint, enabling a priori knowledge of their approximate source region. To each event, we apply several image processing and geometric techniques with the aim to evaluate whether such methods can provide additional information compared to the study of "normal" intensity images. We are able to identify at least weak eruptive signatures for all events upon careful investigation of remote-sensing data, noting that differently processed images may be needed to properly interpret and analyse elusive observations. We also find that the effectiveness of geometric techniques strongly depends on the CME propagation direction with respect to the observers and the relative spacecraft separation. Being able to observe and therefore forecast stealth CMEs is of great importance in the context of space weather, since such events are occasionally the solar counterparts of so-called 'problem geomagnetic storms'. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.07571v1-abstract-full').style.display = 'none'; document.getElementById('2106.07571v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 June, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">26 pages, 8 figures, 1 table, accepted for publication in Frontiers in Astronomy and Space Sciences</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.14960">arXiv:2104.14960</a> <span> [<a href="https://arxiv.org/pdf/2104.14960">pdf</a>, <a href="https://arxiv.org/format/2104.14960">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> </div> <p class="title is-5 mathjax"> Signatures of coronal hole substructure in the solar wind: combined Solar Orbiter remote sensing and in situ measurements </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Horbury%2C+T+S">T. S. Horbury</a>, <a href="/search/astro-ph?searchtype=author&query=Laker%2C+R">R. Laker</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Steinvall%2C+K">K. Steinvall</a>, <a href="/search/astro-ph?searchtype=author&query=Maksimovic%2C+M">M. Maksimovic</a>, <a href="/search/astro-ph?searchtype=author&query=Livi%2C+S">S. Livi</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auchere%2C+F">F. Auchere</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Khotyaintsev%2C+Y+V">Yu. V. Khotyaintsev</a>, <a href="/search/astro-ph?searchtype=author&query=Woodham%2C+L">L. Woodham</a>, <a href="/search/astro-ph?searchtype=author&query=Matteini%2C+L">L. Matteini</a>, <a href="/search/astro-ph?searchtype=author&query=Stawarz%2C+J">J. Stawarz</a>, <a href="/search/astro-ph?searchtype=author&query=Woolley%2C+T">T. Woolley</a>, <a href="/search/astro-ph?searchtype=author&query=Bale%2C+S+D">S. D. Bale</a>, <a href="/search/astro-ph?searchtype=author&query=Rouillard%2C+A">A. Rouillard</a>, <a href="/search/astro-ph?searchtype=author&query=O%27Brien%2C+H">H. O'Brien</a>, <a href="/search/astro-ph?searchtype=author&query=Evans%2C+V">V. Evans</a>, <a href="/search/astro-ph?searchtype=author&query=Angelini%2C+V">V. Angelini</a>, <a href="/search/astro-ph?searchtype=author&query=Owen%2C+C">C. Owen</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Nicula%2C+B">B. Nicula</a>, <a href="/search/astro-ph?searchtype=author&query=Muller%2C+D">D. Muller</a>, <a href="/search/astro-ph?searchtype=author&query=Zouganelis%2C+I">I. Zouganelis</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2104.14960v1-abstract-short" style="display: inline;"> Context. The Sun's complex corona is the source of the solar wind and interplanetary magnetic field. While the large scale morphology is well understood, the impact of variations in coronal properties on the scale of a few degrees on properties of the interplanetary medium is not known. Solar Orbiter, carrying both remote sensing and in situ instruments into the inner solar system, is intended to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.14960v1-abstract-full').style.display = 'inline'; document.getElementById('2104.14960v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.14960v1-abstract-full" style="display: none;"> Context. The Sun's complex corona is the source of the solar wind and interplanetary magnetic field. While the large scale morphology is well understood, the impact of variations in coronal properties on the scale of a few degrees on properties of the interplanetary medium is not known. Solar Orbiter, carrying both remote sensing and in situ instruments into the inner solar system, is intended to make these connections better than ever before. Aims. We combine remote sensing and in situ measurements from Solar Orbiter's first perihelion at 0.5 AU to study the fine scale structure of the solar wind from the equatorward edge of a polar coronal hole with the aim of identifying characteristics of the corona which can explain the in situ variations. Methods. We use in situ measurements of the magnetic field, density and solar wind speed to identify structures on scales of hours at the spacecraft. Using Potential Field Source Surface mapping we estimate the source locations of the measured solar wind as a function of time and use EUI images to characterise these solar sources. Results. We identify small scale stream interactions in the solar wind with compressed magnetic field and density along with speed variations which are associated with corrugations in the edge of the coronal hole on scales of several degrees, demonstrating that fine scale coronal structure can directly influence solar wind properties and drive variations within individual streams. Conclusions. This early analysis already demonstrates the power of Solar Orbiter's combined remote sensing and in situ payload and shows that with future, closer perihelia it will be possible dramatically to improve our knowledge of the coronal sources of fine scale solar wind structure, which is important both for understanding the phenomena driving the solar wind and predicting its impacts at the Earth and elsewhere. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.14960v1-abstract-full').style.display = 'none'; document.getElementById('2104.14960v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Submitted to Astronomy and Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2104.03382">arXiv:2104.03382</a> <span> [<a href="https://arxiv.org/pdf/2104.03382">pdf</a>, <a href="https://arxiv.org/format/2104.03382">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202140380">10.1051/0004-6361/202140380 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Extreme UV quiet Sun brightenings observed by Solar Orbiter/EUI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Auchere%2C+F">F. Auchere</a>, <a href="/search/astro-ph?searchtype=author&query=Long%2C+D+M">D. M. Long</a>, <a href="/search/astro-ph?searchtype=author&query=Soubrie%2C+E">E. Soubrie</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+M+M+A+N">M. Mierla A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Schuhle%2C+U">U. Schuhle</a>, <a href="/search/astro-ph?searchtype=author&query=Antolin%2C+P">P. Antolin</a>, <a href="/search/astro-ph?searchtype=author&query=Parenti%2C+L+H+S">L. Harra S. Parenti</a>, <a href="/search/astro-ph?searchtype=author&query=Podladchikova%2C+O">O. Podladchikova</a>, <a href="/search/astro-ph?searchtype=author&query=Cuadrado%2C+R+A">R. Aznar Cuadrado</a>, <a href="/search/astro-ph?searchtype=author&query=Buchlin%2C+E">E. Buchlin</a>, <a href="/search/astro-ph?searchtype=author&query=Dolla%2C+L">L. Dolla</a>, <a href="/search/astro-ph?searchtype=author&query=Verbeeck%2C+C">C. Verbeeck</a>, <a href="/search/astro-ph?searchtype=author&query=Gissot%2C+S">S. Gissot</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Haberreiter%2C+M">M. Haberreiter</a>, <a href="/search/astro-ph?searchtype=author&query=Katsiyannis%2C+A+C">A. C. Katsiyannis</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">L. Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Kraaikamp%2C+E">E. Kraaikamp</a>, <a href="/search/astro-ph?searchtype=author&query=Smith%2C+P+J">P. J. Smith</a>, <a href="/search/astro-ph?searchtype=author&query=Stegen%2C+K">K. Stegen</a>, <a href="/search/astro-ph?searchtype=author&query=Rochus%2C+P">P. Rochus</a>, <a href="/search/astro-ph?searchtype=author&query=Halain%2C+J+P">J. P. Halain</a>, <a href="/search/astro-ph?searchtype=author&query=Jacques%2C+L">L. Jacques</a>, <a href="/search/astro-ph?searchtype=author&query=Thompson%2C+W+T">W. T. Thompson</a> , et al. (1 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2104.03382v1-abstract-short" style="display: inline;"> The goal of this paper is to study the smallest brightening events observed in the EUV quiet Sun. We use commissioning data taken by the EUI instrument onboard the recently launched Solar Orbiter mission. On 2020 May 30, EUI was situated at 0.556AU from the Sun. Its HRIEUV telescope 17.4nm passband reached an exceptionally high two-pixel spatial resolution of 400km. The size and duration of small-… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.03382v1-abstract-full').style.display = 'inline'; document.getElementById('2104.03382v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2104.03382v1-abstract-full" style="display: none;"> The goal of this paper is to study the smallest brightening events observed in the EUV quiet Sun. We use commissioning data taken by the EUI instrument onboard the recently launched Solar Orbiter mission. On 2020 May 30, EUI was situated at 0.556AU from the Sun. Its HRIEUV telescope 17.4nm passband reached an exceptionally high two-pixel spatial resolution of 400km. The size and duration of small-scale structures is determined in the HRIEUV data, while their height is estimated from triangulation with the simultaneous SDO/AIA data. This is the first stereoscopy of small scale brightenings at high resolution. We observed small localised brightenings ("campfires") in a quiet Sun region with lengthscales between 400km and 4000km and durations between 10 and 200s. The smallest and weakest of these HRIEUV brightenings have not been observed before. Simultaneous HRILYA observations do not show localised brightening events, but the locations of the HRIEUV events correspond clearly to the chromospheric network. Comparison with simultaneous AIA images shows that most events can also be identified in the 17.1nm, 19.3nm, 21.1nm, and 30.4nm passbands of AIA, although they appear weaker and blurred. DEM analysis indicates coronal temperatures peaking at log(T)~6.1-6.15. We determined the height of a few campfires, which is between 1000 and 5000km above the photosphere. We conclude that "campfires" are mostly coronal in nature and are rooted in the magnetic flux concentrations of the chromospheric network. We interpret these events as a new extension to the flare/microflare/nanoflare family. Given their low height, the EUI "campfires" could be a new element of the fine structure of the transition region/low corona: apexes of small-scale loops that are internally heated to coronal temperatures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2104.03382v1-abstract-full').style.display = 'none'; document.getElementById('2104.03382v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 April, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">12 pages, 14 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 656, L4 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.07569">arXiv:2102.07569</a> <span> [<a href="https://arxiv.org/pdf/2102.07569">pdf</a>, <a href="https://arxiv.org/format/2102.07569">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202040226">10.1051/0004-6361/202040226 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Exploring the radial evolution of Interplanetary Coronal Mass Ejections using EUHFORIA </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Scolini%2C+C">Camilla Scolini</a>, <a href="/search/astro-ph?searchtype=author&query=Dasso%2C+S">Sergio Dasso</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Poedts%2C+S">Stefaan Poedts</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.07569v1-abstract-short" style="display: inline;"> Coronal Mass Ejections (CMEs) are large-scale eruptions from the Sun into interplanetary space. Despite being major space weather drivers, our knowledge of the CME properties in the inner heliosphere remains constrained by the scarcity of observations at distances other than 1 au. Furthermore, most CMEs are observed in situ by single spacecraft, requiring numerical models to complement the sparse… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.07569v1-abstract-full').style.display = 'inline'; document.getElementById('2102.07569v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.07569v1-abstract-full" style="display: none;"> Coronal Mass Ejections (CMEs) are large-scale eruptions from the Sun into interplanetary space. Despite being major space weather drivers, our knowledge of the CME properties in the inner heliosphere remains constrained by the scarcity of observations at distances other than 1 au. Furthermore, most CMEs are observed in situ by single spacecraft, requiring numerical models to complement the sparse observations available. We aim to assess the ability of the linear force-free spheromak CME model in EUHFORIA to describe the radial evolution of interplanetary CMEs, yielding new context for observational studies. We model one well-studied CME, and investigate its radial evolution by placing virtual spacecraft along the Sun-Earth line in the simulation domain. To directly compare observational and modelling results, we characterise the interplanetary CME signatures between 0.2 and 1.9 au from modelled time series, exploiting techniques traditionally employed to analyse real in situ data. Results show that the modelled radial evolution of the mean solar wind and CME values is consistent with observational and theoretical expectations. The CME expands as a consequence of the decaying pressure in the surrounding wind: the expansion is rapid within 0.4 au, and moderate at larger distances. The early rapid expansion could not explain the overestimated CME radial size in our simulation, suggesting this is an intrinsic limitation of the spheromak geometry used. The magnetic field profile indicates a relaxation of the CME during propagation, while ageing is most probably not a substantial source of magnetic asymmetry beyond 0.4 au. We also report a CME wake that is significantly shorter than suggested by observations. Overall, EUHFORIA provides a consistent description of the radial evolution of solar wind and CMEs; nevertheless, improvements are required to better reproduce the CME radial extension. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.07569v1-abstract-full').style.display = 'none'; document.getElementById('2102.07569v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 649, A69 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2102.05514">arXiv:2102.05514</a> <span> [<a href="https://arxiv.org/pdf/2102.05514">pdf</a>, <a href="https://arxiv.org/format/2102.05514">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2020SW002654">10.1029/2020SW002654 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> CME Magnetic Structure and IMF Preconditioning Affecting SEP Transport </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Kilpua%2C+E+K+J">Emilia K. J. Kilpua</a>, <a href="/search/astro-ph?searchtype=author&query=Witasse%2C+O">Olivier Witasse</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+D">David Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=S%C3%A1nchez-Cano%2C+B">Beatriz S谩nchez-Cano</a>, <a href="/search/astro-ph?searchtype=author&query=Weiss%2C+A+J">Andreas J. Weiss</a>, <a href="/search/astro-ph?searchtype=author&query=Nieves-Chinchilla%2C+T">Teresa Nieves-Chinchilla</a>, <a href="/search/astro-ph?searchtype=author&query=M%C3%B6stl%2C+C">Christian M枚stl</a>, <a href="/search/astro-ph?searchtype=author&query=Jian%2C+L+K">Lan K. Jian</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">Marilena Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Guo%2C+J">Jingnan Guo</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Lowrance%2C+P+J">Patrick J. Lowrance</a>, <a href="/search/astro-ph?searchtype=author&query=Isavnin%2C+A">Alexey Isavnin</a>, <a href="/search/astro-ph?searchtype=author&query=Turc%2C+L">Lucile Turc</a>, <a href="/search/astro-ph?searchtype=author&query=Futaana%2C+Y">Yoshifumi Futaana</a>, <a href="/search/astro-ph?searchtype=author&query=Holmstr%C3%B6m%2C+M">Mats Holmstr枚m</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2102.05514v1-abstract-short" style="display: inline;"> Coronal mass ejections (CMEs) and solar energetic particles (SEPs) are two phenomena that can cause severe space weather effects throughout the heliosphere. The evolution of CMEs, especially in terms of their magnetic structure, and the configuration of the interplanetary magnetic field (IMF) that influences the transport of SEPs are currently areas of active research. These two aspects are not ne… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05514v1-abstract-full').style.display = 'inline'; document.getElementById('2102.05514v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.05514v1-abstract-full" style="display: none;"> Coronal mass ejections (CMEs) and solar energetic particles (SEPs) are two phenomena that can cause severe space weather effects throughout the heliosphere. The evolution of CMEs, especially in terms of their magnetic structure, and the configuration of the interplanetary magnetic field (IMF) that influences the transport of SEPs are currently areas of active research. These two aspects are not necessarily independent of each other, especially during solar maximum when multiple eruptive events can occur close in time. Accordingly, we present the analysis of a CME that erupted on 2012 May 11 (SOL2012-05-11) and an SEP event following an eruption that took place on 2012 May 17 (SOL2012-05-17). After observing the May 11 CME using remote-sensing data from three viewpoints, we evaluate its propagation through interplanetary space using several models. Then, we analyse in-situ measurements from five predicted impact locations (Venus, Earth, the Spitzer Space Telescope, the Mars Science Laboratory en route to Mars, and Mars) in order to search for CME signatures. We find that all in-situ locations detect signatures of an SEP event, which we trace back to the May 17 eruption. These findings suggest that the May 11 CME provided a direct magnetic connectivity for the efficient transport of SEPs. We discuss the space weather implications of CME evolution, regarding in particular its magnetic structure, and CME-driven IMF preconditioning that facilitates SEP transport. Finally, this work remarks the importance of using data from multiple spacecraft, even those that do not include space weather research as their primary objective. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05514v1-abstract-full').style.display = 'none'; document.getElementById('2102.05514v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 February, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2021. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">50 pages, 14 figures, 2 tables, accepted for publication in Space Weather</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2010.10832">arXiv:2010.10832</a> <span> [<a href="https://arxiv.org/pdf/2010.10832">pdf</a>, <a href="https://arxiv.org/format/2010.10832">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/abc0e8">10.3847/2041-8213/abc0e8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Particle-In-Cell simulation of whistler heat flux instabilities in the solar wind: heat flux regulation and electron halo formation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Micera%2C+A">A. Micera</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=L%C3%B3pez%2C+R+A">R. A. L贸pez</a>, <a href="/search/astro-ph?searchtype=author&query=Innocenti%2C+M+E">M. E. Innocenti</a>, <a href="/search/astro-ph?searchtype=author&query=Lazar%2C+M">M. Lazar</a>, <a href="/search/astro-ph?searchtype=author&query=Boella%2C+E">E. Boella</a>, <a href="/search/astro-ph?searchtype=author&query=Lapenta%2C+G">G. Lapenta</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2010.10832v2-abstract-short" style="display: inline;"> We present results of two-dimensional fully kinetic Particle-In-Cell simulation in order to shed light on the role of whistler waves in the scattering of strahl electrons and in the heat flux regulation in the solar wind. We model the electron velocity distribution function as initially composed of core and strahl populations as typically encountered in the near-Sun solar wind as observed by Parke… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.10832v2-abstract-full').style.display = 'inline'; document.getElementById('2010.10832v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2010.10832v2-abstract-full" style="display: none;"> We present results of two-dimensional fully kinetic Particle-In-Cell simulation in order to shed light on the role of whistler waves in the scattering of strahl electrons and in the heat flux regulation in the solar wind. We model the electron velocity distribution function as initially composed of core and strahl populations as typically encountered in the near-Sun solar wind as observed by Parker Solar Probe. We demonstrate that, as a consequence of the evolution of the electron velocity distribution function, two branches of the whistler heat flux instability can be excited, which can drive whistler waves propagating in the direction oblique or parallel to the background magnetic field. First, oblique whistler waves induce pitch-angle scattering of strahl electrons, towards higher perpendicular velocities. This leads to the broadening of the strahl pitch angle distribution and hence to the formation of a halo-like population at the expense of the strahl. Later on, the electron velocity distribution function experiences the effect of parallel whistler waves, which contributes to the redistribution of the particles scattered in the perpendicular direction into a more symmetric halo, in agreement with observations. Simulation results show a remarkable agreement with the linear theory of the oblique whistler heat flux instability. The process is accompanied by a significant decrease of the heat flux carried by the strahl population. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2010.10832v2-abstract-full').style.display = 'none'; document.getElementById('2010.10832v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.10772">arXiv:2009.10772</a> <span> [<a href="https://arxiv.org/pdf/2009.10772">pdf</a>, <a href="https://arxiv.org/format/2009.10772">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/202038445">10.1051/0004-6361/202038445 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Solar Orbiter Science Activity Plan: translating solar and heliospheric physics questions into action </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Zouganelis%2C+I">I. Zouganelis</a>, <a href="/search/astro-ph?searchtype=author&query=De+Groof%2C+A">A. De Groof</a>, <a href="/search/astro-ph?searchtype=author&query=Walsh%2C+A+P">A. P. Walsh</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+D+R">D. R. Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Mueller%2C+D">D. Mueller</a>, <a href="/search/astro-ph?searchtype=author&query=Cyr%2C+O+C+S">O. C. St Cyr</a>, <a href="/search/astro-ph?searchtype=author&query=Auchere%2C+F">F. Auchere</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">D. Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Fludra%2C+A">A. Fludra</a>, <a href="/search/astro-ph?searchtype=author&query=Horbury%2C+T+S">T. S. Horbury</a>, <a href="/search/astro-ph?searchtype=author&query=Howard%2C+R+A">R. A. Howard</a>, <a href="/search/astro-ph?searchtype=author&query=Krucker%2C+S">S. Krucker</a>, <a href="/search/astro-ph?searchtype=author&query=Maksimovic%2C+M">M. Maksimovic</a>, <a href="/search/astro-ph?searchtype=author&query=Owen%2C+C+J">C. J. Owen</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriiguez-Pacheco%2C+J">J. Rodriiguez-Pacheco</a>, <a href="/search/astro-ph?searchtype=author&query=Romoli%2C+M">M. Romoli</a>, <a href="/search/astro-ph?searchtype=author&query=Solanki%2C+S+K">S. K. Solanki</a>, <a href="/search/astro-ph?searchtype=author&query=Watson%2C+C">C. Watson</a>, <a href="/search/astro-ph?searchtype=author&query=Sanchez%2C+L">L. Sanchez</a>, <a href="/search/astro-ph?searchtype=author&query=Lefort%2C+J">J. Lefort</a>, <a href="/search/astro-ph?searchtype=author&query=Osuna%2C+P">P. Osuna</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+H+R">H. R. Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Nieves-Chinchilla%2C+T">T. Nieves-Chinchilla</a>, <a href="/search/astro-ph?searchtype=author&query=Abbo%2C+L">L. Abbo</a>, <a href="/search/astro-ph?searchtype=author&query=Alexandrova%2C+O">O. Alexandrova</a> , et al. (160 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.10772v1-abstract-short" style="display: inline;"> Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.10772v1-abstract-full').style.display = 'inline'; document.getElementById('2009.10772v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.10772v1-abstract-full" style="display: none;"> Solar Orbiter is the first space mission observing the solar plasma both in situ and remotely, from a close distance, in and out of the ecliptic. The ultimate goal is to understand how the Sun produces and controls the heliosphere, filling the Solar System and driving the planetary environments. With six remote-sensing and four in-situ instrument suites, the coordination and planning of the operations are essential to address the following four top-level science questions: (1) What drives the solar wind and where does the coronal magnetic field originate? (2) How do solar transients drive heliospheric variability? (3) How do solar eruptions produce energetic particle radiation that fills the heliosphere? (4) How does the solar dynamo work and drive connections between the Sun and the heliosphere? Maximising the mission's science return requires considering the characteristics of each orbit, including the relative position of the spacecraft to Earth (affecting downlink rates), trajectory events (such as gravitational assist manoeuvres), and the phase of the solar activity cycle. Furthermore, since each orbit's science telemetry will be downloaded over the course of the following orbit, science operations must be planned at mission level, rather than at the level of individual orbits. It is important to explore the way in which those science questions are translated into an actual plan of observations that fits into the mission, thus ensuring that no opportunities are missed. First, the overarching goals are broken down into specific, answerable questions along with the required observations and the so-called Science Activity Plan (SAP) is developed to achieve this. The SAP groups objectives that require similar observations into Solar Orbiter Observing Plans (SOOPs), resulting in a strategic, top-level view of the optimal opportunities for science observations during the mission lifetime. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.10772v1-abstract-full').style.display = 'none'; document.getElementById('2009.10772v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 1 figure, accepted by Astronomy & Astrophysics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 642, A3 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2004.09658">arXiv:2004.09658</a> <span> [<a href="https://arxiv.org/pdf/2004.09658">pdf</a>, <a href="https://arxiv.org/format/2004.09658">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab89a8">10.3847/1538-4357/ab89a8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A new facility for airborne solar astronomy: NASA's WB-57 at the 2017 total solar eclipse </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Caspi%2C+A">Amir Caspi</a>, <a href="/search/astro-ph?searchtype=author&query=Seaton%2C+D+B">Daniel B. Seaton</a>, <a href="/search/astro-ph?searchtype=author&query=Tsang%2C+C+C+C">Constantine C. C. Tsang</a>, <a href="/search/astro-ph?searchtype=author&query=DeForest%2C+C+E">Craig E. DeForest</a>, <a href="/search/astro-ph?searchtype=author&query=Bryans%2C+P">Paul Bryans</a>, <a href="/search/astro-ph?searchtype=author&query=DeLuca%2C+E+E">Edward E. DeLuca</a>, <a href="/search/astro-ph?searchtype=author&query=Tomczyk%2C+S">Steven Tomczyk</a>, <a href="/search/astro-ph?searchtype=author&query=Burkepile%2C+J+T">Joan T. Burkepile</a>, <a href="/search/astro-ph?searchtype=author&query=Casey%2C+T+%22">Thomas "Tony" Casey</a>, <a href="/search/astro-ph?searchtype=author&query=Collier%2C+J">John Collier</a>, <a href="/search/astro-ph?searchtype=author&query=Darrow%2C+D+%22">Donald "DD" Darrow</a>, <a href="/search/astro-ph?searchtype=author&query=Del+Rosso%2C+D">Dominic Del Rosso</a>, <a href="/search/astro-ph?searchtype=author&query=Durda%2C+D+D">Daniel D. Durda</a>, <a href="/search/astro-ph?searchtype=author&query=Gallagher%2C+P+T">Peter T. Gallagher</a>, <a href="/search/astro-ph?searchtype=author&query=Golub%2C+L">Leon Golub</a>, <a href="/search/astro-ph?searchtype=author&query=Jacyna%2C+M">Matthew Jacyna</a>, <a href="/search/astro-ph?searchtype=author&query=Johnson%2C+D+%22">David "DJ" Johnson</a>, <a href="/search/astro-ph?searchtype=author&query=Judge%2C+P+G">Philip G. Judge</a>, <a href="/search/astro-ph?searchtype=author&query=Klemm%2C+C+%22">Cary "Diddle" Klemm</a>, <a href="/search/astro-ph?searchtype=author&query=Laurent%2C+G+T">Glenn T. Laurent</a>, <a href="/search/astro-ph?searchtype=author&query=Lewis%2C+J">Johanna Lewis</a>, <a href="/search/astro-ph?searchtype=author&query=Mallini%2C+C+J">Charles J. Mallini</a>, <a href="/search/astro-ph?searchtype=author&query=Parent%2C+T+%22">Thomas "Duster" Parent</a>, <a href="/search/astro-ph?searchtype=author&query=Propp%2C+T">Timothy Propp</a>, <a href="/search/astro-ph?searchtype=author&query=Steffl%2C+A+J">Andrew J. Steffl</a> , et al. (6 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2004.09658v1-abstract-short" style="display: inline;"> NASA's WB-57 High Altitude Research Program provides a deployable, mobile, stratospheric platform for scientific research. Airborne platforms are of particular value for making coronal observations during total solar eclipses because of their ability both to follow the Moon's shadow and to get above most of the atmospheric airmass that can interfere with astronomical observations. We used the 2017… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.09658v1-abstract-full').style.display = 'inline'; document.getElementById('2004.09658v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2004.09658v1-abstract-full" style="display: none;"> NASA's WB-57 High Altitude Research Program provides a deployable, mobile, stratospheric platform for scientific research. Airborne platforms are of particular value for making coronal observations during total solar eclipses because of their ability both to follow the Moon's shadow and to get above most of the atmospheric airmass that can interfere with astronomical observations. We used the 2017 Aug 21 eclipse as a pathfinding mission for high-altitude airborne solar astronomy, using the existing high-speed visible-light and near-/mid-wave infrared imaging suite mounted in the WB-57 nose cone. In this paper, we describe the aircraft, the instrument, and the 2017 mission; operations and data acquisition; and preliminary analysis of data quality from the existing instrument suite. We describe benefits and technical limitations of this platform for solar and other astronomical observations. We present a preliminary analysis of the visible-light data quality and discuss the limiting factors that must be overcome with future instrumentation. We conclude with a discussion of lessons learned from this pathfinding mission and prospects for future research at upcoming eclipses, as well as an evaluation of the capabilities of the WB-57 platform for future solar astronomy and general astronomical observation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2004.09658v1-abstract-full').style.display = 'none'; document.getElementById('2004.09658v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 20 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">17 pages, 10 figures; accepted for publication by the Astrophysical Journal</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, Vol. 895, Issue 2, 131 (14pp); 2020 June 1 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2003.12350">arXiv:2003.12350</a> <span> [<a href="https://arxiv.org/pdf/2003.12350">pdf</a>, <a href="https://arxiv.org/format/2003.12350">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab8194">10.3847/1538-4357/ab8194 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Properties of Streamer Wave Events Observed During the STEREO Era </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Decraemer%2C+B">Bieke Decraemer</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Van+Doorsselaere%2C+T">Tom Van Doorsselaere</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2003.12350v1-abstract-short" style="display: inline;"> Transverse waves are sometimes observed in solar helmet streamers, typically after the passage of a coronal mass ejection (CME). The CME-driven shock wave moves the streamer sideways, and a decaying oscillation of the streamer is observed after the CME passage. Previous works generally reported observations of streamer oscillations taken from a single vantage point (typically the SOHO spacecraft).… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.12350v1-abstract-full').style.display = 'inline'; document.getElementById('2003.12350v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2003.12350v1-abstract-full" style="display: none;"> Transverse waves are sometimes observed in solar helmet streamers, typically after the passage of a coronal mass ejection (CME). The CME-driven shock wave moves the streamer sideways, and a decaying oscillation of the streamer is observed after the CME passage. Previous works generally reported observations of streamer oscillations taken from a single vantage point (typically the SOHO spacecraft). We conduct a data survey searching for streamer wave events observed by the COR2 coronagraphs onboard the STEREO spacecraft. For the first time, we report observations of streamer wave events from multiple vantage points, by using the COR2 instrument on both STEREO A and B, as well as the SOHO/LASCO C2+C3 coronagraphs. We investigate the properties of streamer waves by comparing the different events and performing a statistical analysis. Common observational features give us additional insight on the physical nature of streamer wave events. The most important conclusion is that there appears to be no relation between the speed of the CME and the phase speed of the resulting streamer wave, indicating that the streamer wave speed is determined by the physical properties of the streamer rather than the properties of the CME. This result makes streamer waves events excellent candidates for coronal seismology studies. From a comparison between the measured phase speeds and the phase speeds calculated from the measured periods and wavelengths, we could determine that the speed of the post-shock solar wind flow in our streamers is around 300 $\mathrm{km \ s}^{-1}$. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2003.12350v1-abstract-full').style.display = 'none'; document.getElementById('2003.12350v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 27 March, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 12 figures, 1 table. Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1908.05034">arXiv:1908.05034</a> <span> [<a href="https://arxiv.org/pdf/1908.05034">pdf</a>, <a href="https://arxiv.org/format/1908.05034">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab3b58">10.3847/1538-4357/ab3b58 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Three-dimensional Density Structure of a Solar Coronal Streamer Observed by SOHO/LASCO and STEREO/COR2 in Quadrature </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Decraemer%2C+B">Bieke Decraemer</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Van+Doorsselaere%2C+T">Tom Van Doorsselaere</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1908.05034v1-abstract-short" style="display: inline;"> Helmet streamers are a prominent manifestation of magnetic structures with current sheets in the solar corona. These large-scale structures are regions with high plasma density, overlying active regions and filament channels. We investigate the three-dimensional (3D) structure of a coronal streamer, observed simultaneously by white-light coronagraphs from two vantage points near quadrature (SOHO/L… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.05034v1-abstract-full').style.display = 'inline'; document.getElementById('1908.05034v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1908.05034v1-abstract-full" style="display: none;"> Helmet streamers are a prominent manifestation of magnetic structures with current sheets in the solar corona. These large-scale structures are regions with high plasma density, overlying active regions and filament channels. We investigate the three-dimensional (3D) structure of a coronal streamer, observed simultaneously by white-light coronagraphs from two vantage points near quadrature (SOHO/LASCO and STEREO/COR2). We design a forward model based on plausible assumptions about the 3D streamer structure taken from physical models (a plasma slab centered around a current sheet). The streamer stalk is approximated by a plasma slab, with electron density that is characterized by three separate functions describing the radial, transverse and face-on profiles respectively. For the first time, we simultaneously fit the observational data from SOHO and STEREO using a multivariate minimization algorithm. The streamer plasma sheet contains a number of brighter and darker ray-like structures with the density contrast up to about a factor 3 between them. The densities derived using polarized and unpolarized data are similar. We demonstrate that our model corresponds well to the observations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1908.05034v1-abstract-full').style.display = 'none'; document.getElementById('1908.05034v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 August, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages, 16 figures, 2 tables. Accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1906.01353">arXiv:1906.01353</a> <span> [<a href="https://arxiv.org/pdf/1906.01353">pdf</a>, <a href="https://arxiv.org/format/1906.01353">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/1538-4357/ab1850">10.3847/1538-4357/ab1850 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Multipoint study of successive coronal mass ejections driving moderate disturbances at 1 AU </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Scolini%2C+C">Camilla Scolini</a>, <a href="/search/astro-ph?searchtype=author&query=Barnes%2C+D">David Barnes</a>, <a href="/search/astro-ph?searchtype=author&query=Magdaleni%C4%87%2C+J">Jasmina Magdaleni膰</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">Matthew J. West</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Rodriguez%2C+L">Luciano Rodriguez</a>, <a href="/search/astro-ph?searchtype=author&query=Mierla%2C+M">Marilena Mierla</a>, <a href="/search/astro-ph?searchtype=author&query=Good%2C+S+W">Simon W. Good</a>, <a href="/search/astro-ph?searchtype=author&query=Morosan%2C+D+E">Diana E. Morosan</a>, <a href="/search/astro-ph?searchtype=author&query=Kilpua%2C+E+K+J">Emilia K. J. Kilpua</a>, <a href="/search/astro-ph?searchtype=author&query=Pomoell%2C+J">Jens Pomoell</a>, <a href="/search/astro-ph?searchtype=author&query=Poedts%2C+S">Stefaan Poedts</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1906.01353v1-abstract-short" style="display: inline;"> We analyse in this work the propagation and geoeffectiveness of four successive coronal mass ejections (CMEs) that erupted from the Sun during 21--23 May 2013 and that were detected in interplanetary space by the Wind and/or STEREO-A spacecraft. All these CMEs featured critical aspects for understanding so-called "problem space weather storms" at Earth. In the first three events a limb CMEs result… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.01353v1-abstract-full').style.display = 'inline'; document.getElementById('1906.01353v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1906.01353v1-abstract-full" style="display: none;"> We analyse in this work the propagation and geoeffectiveness of four successive coronal mass ejections (CMEs) that erupted from the Sun during 21--23 May 2013 and that were detected in interplanetary space by the Wind and/or STEREO-A spacecraft. All these CMEs featured critical aspects for understanding so-called "problem space weather storms" at Earth. In the first three events a limb CMEs resulted in moderately geoeffective in-situ structures at their target location in terms of the disturbance storm time (Dst) index (either measured or estimated). The fourth CME, which also caused a moderate geomagnetic response, erupted from close to the disc centre as seen from Earth, but it was not visible in coronagraph images from the spacecraft along the Sun--Earth line and appeared narrow and faint from off-angle viewpoints. Making the correct connection between CMEs at the Sun and their in-situ counterparts is often difficult for problem storms. We investigate these four CMEs using multiwavelength and multipoint remote-sensing observations (extreme ultraviolet, white light, and radio), aided by 3D heliospheric modelling, in order to follow their propagation in the corona and in interplanetary space and to assess their impact at 1 AU. Finally, we emphasise the difficulties in forecasting moderate space weather effects provoked by problematic and ambiguous events and the importance of multispacecraft data for observing and modelling problem storms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1906.01353v1-abstract-full').style.display = 'none'; document.getElementById('1906.01353v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 10 figures, 3 tables, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1812.03990">arXiv:1812.03990</a> <span> [<a href="https://arxiv.org/pdf/1812.03990">pdf</a>, <a href="https://arxiv.org/ps/1812.03990">ps</a>, <a href="https://arxiv.org/format/1812.03990">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201834584">10.1051/0004-6361/201834584 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Modeling and removal of optical ghosts in the PROBA-3/ASPIICS externally occulted solar coronagraph </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Shestov%2C+S+V">S. V. Shestov</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Seaton%2C+D+B">D. B. Seaton</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1812.03990v1-abstract-short" style="display: inline;"> Context: ASPIICS is a novel externally occulted solar coronagraph, which will be launched onboard the PROBA-3 mission of the European Space Agency. The external occulter will be placed on the first satellite approximately 150 m ahead of the second satellite that will carry an optical instrument. During 6 hours per orbit, the satellites will fly in a precise formation, constituting a giant external… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.03990v1-abstract-full').style.display = 'inline'; document.getElementById('1812.03990v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1812.03990v1-abstract-full" style="display: none;"> Context: ASPIICS is a novel externally occulted solar coronagraph, which will be launched onboard the PROBA-3 mission of the European Space Agency. The external occulter will be placed on the first satellite approximately 150 m ahead of the second satellite that will carry an optical instrument. During 6 hours per orbit, the satellites will fly in a precise formation, constituting a giant externally occulted coronagraph. Large distance between the external occulter and the primary objective will allow observations of the white-light solar corona starting from extremely low heights 1.1RSun. Aims: To analyze influence of optical ghost images formed inside the telescope and develop an algorithm for their removal. Methods: We implement the optical layout of ASPIICS in Zemax and study the ghost behaviour in sequential and non-sequential regimes. We identify sources of the ghost contributions and analyze their geometrical behaviour. Finally we develop a mathematical model and software to calculate ghost images for any given input image. Results: We show that ghost light can be important in the outer part of the field of view, where the coronal signal is weak, since the energy of bright inner corona is redistributed to the outer corona. However the model allows to remove the ghost contribution. Due to a large distance between the external occulter and the primary objective, the primary objective does not produce a significant ghost. The use of the Lyot spot in ASPIICS is not necessary. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1812.03990v1-abstract-full').style.display = 'none'; document.getElementById('1812.03990v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 December, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 13 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 622, A101 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1810.09835">arXiv:1810.09835</a> <span> [<a href="https://arxiv.org/pdf/1810.09835">pdf</a>, <a href="https://arxiv.org/ps/1810.09835">ps</a>, <a href="https://arxiv.org/format/1810.09835">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.3847/2041-8213/aaeace">10.3847/2041-8213/aaeace <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First Detection of Solar Flare Emission in Middle-Ultraviolet Balmer Continuum </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dominique%2C+M">Marie Dominique</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">Andrei N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Heinzel%2C+P">Petr Heinzel</a>, <a href="/search/astro-ph?searchtype=author&query=Dammasch%2C+I+E">Ingolf E. Dammasch</a>, <a href="/search/astro-ph?searchtype=author&query=Wauters%2C+L">Laurence Wauters</a>, <a href="/search/astro-ph?searchtype=author&query=Dolla%2C+L">Laurent Dolla</a>, <a href="/search/astro-ph?searchtype=author&query=Shestov%2C+S">Sergei Shestov</a>, <a href="/search/astro-ph?searchtype=author&query=Kretzschmar%2C+M">Matthieu Kretzschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Machol%2C+J">Janet Machol</a>, <a href="/search/astro-ph?searchtype=author&query=Lapenta%2C+G">Giovanni Lapenta</a>, <a href="/search/astro-ph?searchtype=author&query=Schmutz%2C+W">Werner Schmutz</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1810.09835v1-abstract-short" style="display: inline;"> We present the first detection of solar flare emission at middle-ultraviolet wavelengths around 2000 A by the channel 2 of the Large-Yield RAdiometer (LYRA) onboard the PROBA2 mission. The flare (SOL20170906) was also observed in the channel 1 of LYRA centered at the H I Lyman-伪 line at 1216 A, showing a clear non-thermal profile in both channels. The flare radiation in channel 2 is consistent wit… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.09835v1-abstract-full').style.display = 'inline'; document.getElementById('1810.09835v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.09835v1-abstract-full" style="display: none;"> We present the first detection of solar flare emission at middle-ultraviolet wavelengths around 2000 A by the channel 2 of the Large-Yield RAdiometer (LYRA) onboard the PROBA2 mission. The flare (SOL20170906) was also observed in the channel 1 of LYRA centered at the H I Lyman-伪 line at 1216 A, showing a clear non-thermal profile in both channels. The flare radiation in channel 2 is consistent with the hydrogen Balmer continuum emission produced by an optically thin chromospheric slab heated up to 10000 K. Simultaneous observations in channels 1 and 2 allow the separation of the line emission (primarily from the Lyman-伪 line) from the Balmer continuum emission. Together with the recent detection of the Balmer continuum emission in the near-ultraviolet by IRIS, the LYRA observations strengthen the interpretation of broadband flare emission as the hydrogen recombination continua originating in the chromosphere. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.09835v1-abstract-full').style.display = 'none'; document.getElementById('1810.09835v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 23 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Letters, Vol 867, Iss 2, article id. L24, 2018 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.00155">arXiv:1807.00155</a> <span> [<a href="https://arxiv.org/pdf/1807.00155">pdf</a>, <a href="https://arxiv.org/ps/1807.00155">ps</a>, <a href="https://arxiv.org/format/1807.00155">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s11207-018-1251-3">10.1007/s11207-018-1251-3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Visibility of Prominences using the HeI D3 Line Filter on PROBA-3/ASPIICS Coronagraph </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jej%C4%8Di%C4%8D%2C+S">S. Jej膷i膷</a>, <a href="/search/astro-ph?searchtype=author&query=Heinzel%2C+P">P. Heinzel</a>, <a href="/search/astro-ph?searchtype=author&query=Labrosse%2C+N">N. Labrosse</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Bemporad%2C+A">A. Bemporad</a>, <a href="/search/astro-ph?searchtype=author&query=Fineschi%2C+S">S. Fineschi</a>, <a href="/search/astro-ph?searchtype=author&query=Gun%C3%A1r%2C+S">S. Gun谩r</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1807.00155v1-abstract-short" style="display: inline;"> We determine an optimal width and shape of the narrow-band filter centered around the He\,{\sc i} D$_{3}$ line for prominence and coronal mass ejection (CME) observations with the ASPIICS ({\it Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun}) coronagraph onboard the PROBA-3 ({\it Project for On-board Autonomy}) satellite, to be launched in 2020. We an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.00155v1-abstract-full').style.display = 'inline'; document.getElementById('1807.00155v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.00155v1-abstract-full" style="display: none;"> We determine an optimal width and shape of the narrow-band filter centered around the He\,{\sc i} D$_{3}$ line for prominence and coronal mass ejection (CME) observations with the ASPIICS ({\it Association of Spacecraft for Polarimetric and Imaging Investigation of the Corona of the Sun}) coronagraph onboard the PROBA-3 ({\it Project for On-board Autonomy}) satellite, to be launched in 2020. We analyze He\,{\sc i} D$_{3}$ line intensities for three representative non-LTE prominence models at temperatures 8, 30 and 100~kK computed by the radiative transfer code and the prominence visible-light (VL) emission due to Thomson scattering on the prominence electrons. We compute various useful relations at prominence line-of-sight (LOS) velocities of 0, 100, and 300~km~s$^{-1}$ for 20~脜~wide flat filter and three Gaussian filters with full width at half maximum (FWHM) equal to 5, 10, and 20~脜~to show the relative brightness contribution of the He\,{\sc i} D$_{3}$ line and the prominence VL to the visibility in a given narrow-band filter. We also discuss possible signal contamination by Na\,{\sc i} D$_{1}$ and D$_{2}$ lines which otherwise may be useful to detect comets. Results mainly show: i) an optimal narrow-band filter should be flat or somewhere between flat and Gaussian with FWHM of 20~脜~in order to detect fast moving prominence structures, ii) the maximum emission in the He\,{\sc i} D$_3$ line is at 30~kK and the minimal at 100~kK, and iii) the ratio of emission in the He\,{\sc i} D$_3$ line to the VL emission can provide a useful diagnostic for the temperature of prominence structures. This ratio is up to 10 for hot prominence structures, up to 100 for cool structures and up to 1000 for warm structures. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.00155v1-abstract-full').style.display = 'none'; document.getElementById('1807.00155v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2018. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1801.04204">arXiv:1801.04204</a> <span> [<a href="https://arxiv.org/pdf/1801.04204">pdf</a>, <a href="https://arxiv.org/ps/1801.04204">ps</a>, <a href="https://arxiv.org/format/1801.04204">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/0004-6361/201732386">10.1051/0004-6361/201732386 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Influence of misalignments on performance of externally occulted solar coronagraphs. Application to PROBA-3/ASPIICS </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Shestov%2C+S+V">S. V. Shestov</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1801.04204v1-abstract-short" style="display: inline;"> ASPIICS is a novel externally occulted coronagraph that will be launched onboard the PROBA-3 mission of ESA. The external occulter (EO) will be placed on one satellite ~150 m ahead of the second satellite with an optical instrument. During part of each orbit, the satellites will fly in a precise formation, constituting a giant externally occulted coronagraph. Large distance between the EO and the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.04204v1-abstract-full').style.display = 'inline'; document.getElementById('1801.04204v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.04204v1-abstract-full" style="display: none;"> ASPIICS is a novel externally occulted coronagraph that will be launched onboard the PROBA-3 mission of ESA. The external occulter (EO) will be placed on one satellite ~150 m ahead of the second satellite with an optical instrument. During part of each orbit, the satellites will fly in a precise formation, constituting a giant externally occulted coronagraph. Large distance between the EO and the primary objective will allow observations of the white-light solar corona starting already from ~1.1RSun. We analyze influence of shifts of the satellites and misalignments of optical elements on diffracted light. Based on the quantitative influence of misalignments on diffracted light, we will provide a "recipe" for choosing the size of the internal occulter (IO) to achieve a trade-off between the minimal height of observations and sustainability to possible misalignments. We implement a numerical model of the diffracted light and its propagation through the optical system, and compute intensities of diffracted light throughout the instrument. Our numerical model extends axi-symmetrical model of Rougeot et al. 2017 to non-symmetrical cases. The computations fully confirm main properties of the diffracted light obtained from semi-analytical consideration. Results: relative influences of various misalignments are significantly different. We show that: the IO with R=1.1RSun is large enough to compensate possible misalignments in ASPIICS, apodizing the edge of the IO leads to additional suppression of the diffracted light. Conclusions: the most important misalignment is the tilt of the telescope WRT the line connecting the center of the EO and the entrance aperture. Special care should be taken to co-align the EO and the coronagraph, i.e. co-aligning the diffraction fringe from the EO and the IO. We suggest that the best orientation strategy is to point the coronagraph to the center of the EO. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.04204v1-abstract-full').style.display = 'none'; document.getElementById('1801.04204v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 January, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2018. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">13 pages, 15 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 612, A82 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1302.6525">arXiv:1302.6525</a> <span> [<a href="https://arxiv.org/pdf/1302.6525">pdf</a>, <a href="https://arxiv.org/ps/1302.6525">ps</a>, <a href="https://arxiv.org/format/1302.6525">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Instrumentation and Methods for Astrophysics">astro-ph.IM</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1007/s11207-013-0252-5">10.1007/s11207-013-0252-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The LYRA Instrument Onboard PROBA2: Description and In-Flight Performance </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dominique%2C+M">M. Dominique</a>, <a href="/search/astro-ph?searchtype=author&query=Hochedez%2C+J+-">J. -F. Hochedez</a>, <a href="/search/astro-ph?searchtype=author&query=Schmutz%2C+W">W. Schmutz</a>, <a href="/search/astro-ph?searchtype=author&query=Dammasch%2C+I+E">I. E. Dammasch</a>, <a href="/search/astro-ph?searchtype=author&query=Shapiro%2C+A+I">A. I. Shapiro</a>, <a href="/search/astro-ph?searchtype=author&query=Kretzschmar%2C+M">M. Kretzschmar</a>, <a href="/search/astro-ph?searchtype=author&query=Zhukov%2C+A+N">A. N. Zhukov</a>, <a href="/search/astro-ph?searchtype=author&query=Gillotay%2C+D">D. Gillotay</a>, <a href="/search/astro-ph?searchtype=author&query=Stockman%2C+Y">Y. Stockman</a>, <a href="/search/astro-ph?searchtype=author&query=BenMoussa%2C+A">A. BenMoussa</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1302.6525v1-abstract-short" style="display: inline;"> The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to mid-ultraviolet) solar radiometer onboard the European Space Agency PROBA2 mission that was launched in November 2009. LYRA acquires solar irradiance measurements at a high cadence (nominally 20 Hz) in four broad spectral channels, from soft X-ray to MUV, that have been chosen for their relevance to solar physics, space weather and… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.6525v1-abstract-full').style.display = 'inline'; document.getElementById('1302.6525v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1302.6525v1-abstract-full" style="display: none;"> The Large Yield Radiometer (LYRA) is an XUV-EUV-MUV (soft X-ray to mid-ultraviolet) solar radiometer onboard the European Space Agency PROBA2 mission that was launched in November 2009. LYRA acquires solar irradiance measurements at a high cadence (nominally 20 Hz) in four broad spectral channels, from soft X-ray to MUV, that have been chosen for their relevance to solar physics, space weather and aeronomy. In this article, we briefly review the design of the instrument, give an overview of the data products distributed through the instrument website, and describe the way that data are calibrated. We also briefly present a summary of the main fields of research currently under investigation by the LYRA consortium. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.6525v1-abstract-full').style.display = 'none'; document.getElementById('1302.6525v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 February, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2013. </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Zhukov%2C+A+N&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Zhukov%2C+A+N&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Zhukov%2C+A+N&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" aria-label="Secondary">  <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/about">About</a></li> <li><a href="https://info.arxiv.org/help">Help</a></li> </ul> </div> <div class="column"> <ul class="nav-spaced"> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>contact arXiv</title><desc>Click here to contact arXiv</desc><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg> <a href="https://info.arxiv.org/help/contact.html"> Contact</a> </li> <li> <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><title>subscribe to arXiv mailings</title><desc>Click here to subscribe</desc><path d="M476 3.2L12.5 270.6c-18.1 10.4-15.8 35.6 2.2 43.2L121 358.4l287.3-253.2c5.5-4.9 13.3 2.6 8.6 8.3L176 407v80.5c0 23.6 28.5 32.9 42.5 15.8L282 426l124.6 52.2c14.2 6 30.4-2.9 33-18.2l72-432C515 7.8 493.3-6.8 476 3.2z"/></svg> <a href="https://info.arxiv.org/help/subscribe"> Subscribe</a> </li> </ul> </div> </div> </div>   <div class="column"> <div class="columns"> <div class="column"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/license/index.html">Copyright</a></li> <li><a href="https://info.arxiv.org/help/policies/privacy_policy.html">Privacy Policy</a></li> </ul> </div> <div class="column sorry-app-links"> <ul class="nav-spaced"> <li><a href="https://info.arxiv.org/help/web_accessibility.html">Web Accessibility Assistance</a></li> <li> <p class="help"> <a class="a11y-main-link" href="https://status.arxiv.org" target="_blank">arXiv Operational Status <svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 256 512" class="icon filter-dark_grey" role="presentation"><path d="M224.3 273l-136 136c-9.4 9.4-24.6 9.4-33.9 0l-22.6-22.6c-9.4-9.4-9.4-24.6 0-33.9l96.4-96.4-96.4-96.4c-9.4-9.4-9.4-24.6 0-33.9L54.3 103c9.4-9.4 24.6-9.4 33.9 0l136 136c9.5 9.4 9.5 24.6.1 34z"/></svg></a><br> Get status notifications via <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/email/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" class="icon filter-black" role="presentation"><path d="M502.3 190.8c3.9-3.1 9.7-.2 9.7 4.7V400c0 26.5-21.5 48-48 48H48c-26.5 0-48-21.5-48-48V195.6c0-5 5.7-7.8 9.7-4.7 22.4 17.4 52.1 39.5 154.1 113.6 21.1 15.4 56.7 47.8 92.2 47.6 35.7.3 72-32.8 92.3-47.6 102-74.1 131.6-96.3 154-113.7zM256 320c23.2.4 56.6-29.2 73.4-41.4 132.7-96.3 142.8-104.7 173.4-128.7 5.8-4.5 9.2-11.5 9.2-18.9v-19c0-26.5-21.5-48-48-48H48C21.5 64 0 85.5 0 112v19c0 7.4 3.4 14.3 9.2 18.9 30.6 23.9 40.7 32.4 173.4 128.7 16.8 12.2 50.2 41.8 73.4 41.4z"/></svg>email</a> or <a class="is-link" href="https://subscribe.sorryapp.com/24846f03/slack/new" target="_blank"><svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 448 512" class="icon filter-black" role="presentation"><path d="M94.12 315.1c0 25.9-21.16 47.06-47.06 47.06S0 341 0 315.1c0-25.9 21.16-47.06 47.06-47.06h47.06v47.06zm23.72 0c0-25.9 21.16-47.06 47.06-47.06s47.06 21.16 47.06 47.06v117.84c0 25.9-21.16 47.06-47.06 47.06s-47.06-21.16-47.06-47.06V315.1zm47.06-188.98c-25.9 0-47.06-21.16-47.06-47.06S139 32 164.9 32s47.06 21.16 47.06 47.06v47.06H164.9zm0 23.72c25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06H47.06C21.16 243.96 0 222.8 0 196.9s21.16-47.06 47.06-47.06H164.9zm188.98 47.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06s-21.16 47.06-47.06 47.06h-47.06V196.9zm-23.72 0c0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06V79.06c0-25.9 21.16-47.06 47.06-47.06 25.9 0 47.06 21.16 47.06 47.06V196.9zM283.1 385.88c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06-25.9 0-47.06-21.16-47.06-47.06v-47.06h47.06zm0-23.72c-25.9 0-47.06-21.16-47.06-47.06 0-25.9 21.16-47.06 47.06-47.06h117.84c25.9 0 47.06 21.16 47.06 47.06 0 25.9-21.16 47.06-47.06 47.06H283.1z"/></svg>slack</a> </p> </li> </ul> </div> </div> </div>  </div> </footer> <script src="https://static.arxiv.org/static/base/1.0.0a5/js/member_acknowledgement.js"></script> </body> </html>

CINXE.COM

Search | arXiv e-print repository