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<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=Downs%2C+C&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Downs%2C+C&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Downs%2C+C&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/2410.16555">arXiv:2410.16555</a> <span> [<a href="https://arxiv.org/pdf/2410.16555">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> </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.ado2993">10.1126/science.ado2993 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observing the evolution of the Sun's global coronal magnetic field over eight months </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Yang%2C+Z">Zihao Yang</a>, <a href="/search/astro-ph?searchtype=author&query=Tian%2C+H">Hui Tian</a>, <a href="/search/astro-ph?searchtype=author&query=Tomczyk%2C+S">Steven Tomczyk</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+X">Xianyu Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Gibson%2C+S">Sarah Gibson</a>, <a href="/search/astro-ph?searchtype=author&query=Morton%2C+R+J">Richard J. Morton</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</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="2410.16555v1-abstract-short" style="display: inline;"> The magnetic field in the Sun's corona stores energy that can be released to heat the coronal plasma and drive solar eruptions. Measurements of the global coronal magnetic field have been limited to a few snapshots. We present observations using the Upgraded Coronal Multi-channel Polarimeter, which provided 114 magnetograms of the global corona above the solar limb spanning approximately eight mon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.16555v1-abstract-full').style.display = 'inline'; document.getElementById('2410.16555v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.16555v1-abstract-full" style="display: none;"> The magnetic field in the Sun's corona stores energy that can be released to heat the coronal plasma and drive solar eruptions. Measurements of the global coronal magnetic field have been limited to a few snapshots. We present observations using the Upgraded Coronal Multi-channel Polarimeter, which provided 114 magnetograms of the global corona above the solar limb spanning approximately eight months. We determined the magnetic field distributions at different solar radii in the corona, and monitored the evolution at different latitudes over multiple solar rotations. We found varying field strengths from <1 to 20 Gauss within 1.05-1.6 solar radii and a signature of active longitude in the coronal magnetic field. Coronal models are generally consistent with the observational data, with larger discrepancies in high-latitude regions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.16555v1-abstract-full').style.display = 'none'; document.getElementById('2410.16555v1-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 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">This is the author's version of the work. It is posted here by permission of the AAAS for personal use, not for redistribution. The definitive version was published in Science on October 4, 2024, doi: 10.1126/science.ado2993 (https://www.science.org/doi/10.1126/science.ado2993). Cite this paper as Yang et al. 2024, Science, 386, 76-82</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Science, 386, 76-82 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2410.02134">arXiv:2410.02134</a> <span> [<a href="https://arxiv.org/pdf/2410.02134">pdf</a>, <a href="https://arxiv.org/format/2410.02134">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"> Magnetogram-matching Biot-Savart Law and Decomposition of Vector Magnetograms </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">V. S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">T. T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">J. A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Prazak%2C+M">M. Prazak</a>, <a href="/search/astro-ph?searchtype=author&query=Qiu%2C+J+A">J. A. Qiu</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="2410.02134v1-abstract-short" style="display: inline;"> We generalize a magnetogram-matching Biot-Savart law (BSL) from planar to spherical geometry. For a given coronal current density $\bf{J}$, this law determines the corresponding magnetic field $\tilde{\bf B}$ under the condition that its radial component vanishes at the surface. The superposition of $\tilde{\bf B}$ with a potential magnetic field defined by the given surface radial field, $B_r$, p… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.02134v1-abstract-full').style.display = 'inline'; document.getElementById('2410.02134v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2410.02134v1-abstract-full" style="display: none;"> We generalize a magnetogram-matching Biot-Savart law (BSL) from planar to spherical geometry. For a given coronal current density $\bf{J}$, this law determines the corresponding magnetic field $\tilde{\bf B}$ under the condition that its radial component vanishes at the surface. The superposition of $\tilde{\bf B}$ with a potential magnetic field defined by the given surface radial field, $B_r$, provides the entire magnetic configuration, in which $B_r$ remains unchanged by the currents. Using this approach, we (1) upgrade our regularized BSLs for constructing coronal magnetic flux ropes (MFRs) and (2) propose a new method for decomposing a measured photospheric magnetic field as ${\bf B} = {\bf B}_{\mathrm{pot}} + {\bf B}_T + {\bf B}_{\tilde{S}}$, where the potential, ${\bf B}_{\mathrm{pot}}$, toroidal, ${\bf B}_T$, and tangential poloidal, ${\bf B}_{\tilde{S}}$, fields are determined by $B_r$, $J_r$, and the surface divergence of ${\bf B} - {\bf B}_{\mathrm{pot}}$, respectively, all derived from magnetic data. Our ${\bf B}_T$ is identical to the one in the alternative decomposition by Schuck et al. (2022), while ${\bf B}_{\mathrm{pot}}$ and ${\bf B}_{\tilde{S}}$ are very different from their poloidal fields ${\bf B}_{\mathrm{P}<}$ and ${\bf B}_{\mathrm{P}>}$, which are {\it potential} and refer to {\it different} surface sides. In contrast, our ${\bf B}_{\tilde{S}}$ is generally {\it nonpotential} and, as ${\bf B}_{\mathrm{pot}}$ and ${\bf B}_T$, refers to the {\it same} upper side of the surface, rendering our decomposition more complete and consistent. We demonstrate that it allows one to identify the footprints and projected surface-location of MFRs, as well as the direction and connectivity of their currents, especially for weak or complex configurations, which is very important for modeling and analyzing observed pre-eruptive configurations and their eruptions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2410.02134v1-abstract-full').style.display = 'none'; document.getElementById('2410.02134v1-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> 2 October, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">25 pages, 8 figures, submitted to 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/2402.12805">arXiv:2402.12805</a> <span> [<a href="https://arxiv.org/pdf/2402.12805">pdf</a>, <a href="https://arxiv.org/format/2402.12805">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"> On the Origin of the sudden Heliospheric Open Magnetic Flux Enhancement during the 2014 Pole Reversal </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Heinemann%2C+S+G">Stephan G. Heinemann</a>, <a href="/search/astro-ph?searchtype=author&query=Owens%2C+M+J">Mathew J. Owens</a>, <a href="/search/astro-ph?searchtype=author&query=Temmer%2C+M">Manuela Temmer</a>, <a href="/search/astro-ph?searchtype=author&query=Turtle%2C+J+A">James A. Turtle</a>, <a href="/search/astro-ph?searchtype=author&query=Arge%2C+C+N">Charles N. Arge</a>, <a href="/search/astro-ph?searchtype=author&query=Henney%2C+C+J">Carl J. Henney</a>, <a href="/search/astro-ph?searchtype=author&query=Pomoell%2C+J">Jens Pomoell</a>, <a href="/search/astro-ph?searchtype=author&query=Asvestari%2C+E">Eleanna Asvestari</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Hofmeister%2C+S+J">Stefan J. Hofmeister</a>, <a href="/search/astro-ph?searchtype=author&query=Scolini%2C+C">Camilla Scolini</a>, <a href="/search/astro-ph?searchtype=author&query=Pinto%2C+R+F">Rui F. Pinto</a>, <a href="/search/astro-ph?searchtype=author&query=Madjarska%2C+M+S">Maria S. Madjarska</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="2402.12805v1-abstract-short" style="display: inline;"> Coronal holes are recognized as the primary sources of heliospheric open magnetic flux (OMF). However, a noticeable gap exists between in-situ measured OMF and that derived from remote sensing observations of the Sun. In this study, we investigate the OMF evolution and its connection to solar structures throughout 2014, with special emphasis on the period from September to October, where a sudden… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.12805v1-abstract-full').style.display = 'inline'; document.getElementById('2402.12805v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2402.12805v1-abstract-full" style="display: none;"> Coronal holes are recognized as the primary sources of heliospheric open magnetic flux (OMF). However, a noticeable gap exists between in-situ measured OMF and that derived from remote sensing observations of the Sun. In this study, we investigate the OMF evolution and its connection to solar structures throughout 2014, with special emphasis on the period from September to October, where a sudden and significant OMF increase was reported. By deriving the OMF evolution at 1au, modeling it at the source surface, and analyzing solar photospheric data, we provide a comprehensive analysis of the observed phenomenon. First, we establish a strong correlation between the OMF increase and the solar magnetic field derived from a Potential Field Source Surface (PFSS) model ($cc_{\mathrm{Pearson}}=0.94$). Moreover, we find a good correlation between the OMF and the open flux derived from solar coronal holes ($cc_{\mathrm{Pearson}}=0.88$), although the coronal holes only contain $14-32\%$ of the Sun's total open flux. However, we note that while the OMF evolution correlates with coronal hole open flux, there is no correlation with the coronal hole area evolution ($cc_{\mathrm{Pearson}}=0.0$). The temporal increase in OMF correlates with the vanishing remnant magnetic field at the southern pole, caused by poleward flux circulations from the decay of numerous active regions months earlier. Additionally, our analysis suggests a potential link between the OMF enhancement and the concurrent emergence of the largest active region in solar cycle 24. In conclusion, our study provides insights into the strong increase in OMF observed during September to October 2014. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2402.12805v1-abstract-full').style.display = 'none'; document.getElementById('2402.12805v1-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 February, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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 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/2401.16388">arXiv:2401.16388</a> <span> [<a href="https://arxiv.org/pdf/2401.16388">pdf</a>, <a href="https://arxiv.org/format/2401.16388">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/ad12d2">10.3847/2041-8213/ad12d2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> SuNeRF: 3D reconstruction of the solar EUV corona using Neural Radiance Fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Jarolim%2C+R">Robert Jarolim</a>, <a href="/search/astro-ph?searchtype=author&query=Tremblay%2C+B">Benoit Tremblay</a>, <a href="/search/astro-ph?searchtype=author&query=Mu%C3%B1oz-Jaramillo%2C+A">Andr茅s Mu帽oz-Jaramillo</a>, <a href="/search/astro-ph?searchtype=author&query=Bintsi%2C+K">Kyriaki-Margarita Bintsi</a>, <a href="/search/astro-ph?searchtype=author&query=Jungbluth%2C+A">Anna Jungbluth</a>, <a href="/search/astro-ph?searchtype=author&query=Santos%2C+M">Miraflor Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Vourlidas%2C+A">Angelos Vourlidas</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+J+P">James P. Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Sundaresan%2C+S">Sairam Sundaresan</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</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="2401.16388v1-abstract-short" style="display: inline;"> To understand its evolution and the effects of its eruptive events, the Sun is permanently monitored by multiple satellite missions. The optically-thin emission of the solar plasma and the limited number of viewpoints make it challenging to reconstruct the geometry and structure of the solar atmosphere; however, this information is the missing link to understand the Sun as it is: a three-dimension… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16388v1-abstract-full').style.display = 'inline'; document.getElementById('2401.16388v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2401.16388v1-abstract-full" style="display: none;"> To understand its evolution and the effects of its eruptive events, the Sun is permanently monitored by multiple satellite missions. The optically-thin emission of the solar plasma and the limited number of viewpoints make it challenging to reconstruct the geometry and structure of the solar atmosphere; however, this information is the missing link to understand the Sun as it is: a three-dimensional evolving star. We present a method that enables a complete 3D representation of the uppermost solar layer (corona) observed in extreme ultraviolet (EUV) light. We use a deep learning approach for 3D scene representation that accounts for radiative transfer, to map the entire solar atmosphere from three simultaneous observations. We demonstrate that our approach provides unprecedented reconstructions of the solar poles, and directly enables height estimates of coronal structures, solar filaments, coronal hole profiles, and coronal mass ejections. We validate the approach using model-generated synthetic EUV images, finding that our method accurately captures the 3D geometry of the Sun even from a limited number of 32 ecliptic viewpoints ($|\text{latitude}| \leq 7^\circ$). We quantify uncertainties of our model using an ensemble approach that allows us to estimate the model performance in absence of a ground-truth. Our method enables a novel view of our closest star, and is a breakthrough technology for the efficient use of multi-instrument datasets, which paves the way for future cluster missions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2401.16388v1-abstract-full').style.display = 'none'; document.getElementById('2401.16388v1-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> 29 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">Journal ref:</span> ApJL 961 L31 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2312.14092">arXiv:2312.14092</a> <span> [<a href="https://arxiv.org/pdf/2312.14092">pdf</a>, <a href="https://arxiv.org/format/2312.14092">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"> Solar Eruptions Triggered by Flux Emergence Below or Near a Coronal Flux Rope </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">T. T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Linton%2C+M+G">M. G. Linton</a>, <a href="/search/astro-ph?searchtype=author&query=Leake%2C+J+E">J. E. Leake</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Z. Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">R. Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">V. S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</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="2312.14092v1-abstract-short" style="display: inline;"> Observations have shown a clear association of filament/prominence eruptions with the emergence of magnetic flux in or near filament channels. Magnetohydrodynamic (MHD) simulations have been employed to systematically study the conditions under which such eruptions occur. These simulations to date have modeled filament channels as two-dimensional (2D) flux ropes or 3D uniformly sheared arcades. He… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.14092v1-abstract-full').style.display = 'inline'; document.getElementById('2312.14092v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2312.14092v1-abstract-full" style="display: none;"> Observations have shown a clear association of filament/prominence eruptions with the emergence of magnetic flux in or near filament channels. Magnetohydrodynamic (MHD) simulations have been employed to systematically study the conditions under which such eruptions occur. These simulations to date have modeled filament channels as two-dimensional (2D) flux ropes or 3D uniformly sheared arcades. Here we present MHD simulations of flux emergence into a more realistic configuration consisting of a bipolar active region containing a line-tied 3D flux rope. We use the coronal flux-rope model of Titov et al. (2014) as the initial condition and drive our simulations by imposing boundary conditions extracted from a flux-emergence simulation by Leake et al. (2013). We identify three mechanisms that determine the evolution of the system: (i) reconnection displacing foot points of field lines overlying the coronal flux rope, (ii) changes of the ambient field due to the intrusion of new flux at the boundary, and (iii) interaction of the (axial) electric currents in the pre-existing and newly emerging flux systems. The relative contributions and effects of these mechanisms depend on the properties of the pre-existing and emerging flux systems. Here we focus on the location and orientation of the emerging flux relative to the coronal flux rope. Varying these parameters, we investigate under which conditions an eruption of the latter is triggered. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2312.14092v1-abstract-full').style.display = 'none'; document.getElementById('2312.14092v1-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 December, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">18 pages, 8 figures, accepted for publication by 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/2311.03596">arXiv:2311.03596</a> <span> [<a href="https://arxiv.org/pdf/2311.03596">pdf</a>, <a href="https://arxiv.org/format/2311.03596">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> <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"> CORHEL-CME: An Interactive Tool For Modeling Solar Eruptions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J">Jon Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Torok%2C+T">Tibor Torok</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R">Ronald Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V">Viacheslav Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Reyes%2C+A">Andres Reyes</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">Pete Riley</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="2311.03596v1-abstract-short" style="display: inline;"> Coronal Mass Ejections (CMEs) are immense eruptions of plasma and magnetic fields that are propelled outward from the Sun, sometimes with velocities greater than 2000 km/s. They are responsible for some of the most severe space weather at Earth, including geomagnetic storms and solar energetic particle (SEP) events. We have developed CORHEL-CME, an interactive tool that allows non-expert users to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.03596v1-abstract-full').style.display = 'inline'; document.getElementById('2311.03596v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2311.03596v1-abstract-full" style="display: none;"> Coronal Mass Ejections (CMEs) are immense eruptions of plasma and magnetic fields that are propelled outward from the Sun, sometimes with velocities greater than 2000 km/s. They are responsible for some of the most severe space weather at Earth, including geomagnetic storms and solar energetic particle (SEP) events. We have developed CORHEL-CME, an interactive tool that allows non-expert users to routinely model multiple CMEs in a realistic coronal and heliospheric environment. The tool features a web-based user interface that allows the user to select a time period of interest, and employs RBSL flux ropes to create stable and unstable pre-eruptive configurations within a background global magnetic field. The properties of these configurations can first be explored in a zero-beta magnetohydrodynamic (MHD) model, followed by complete CME simulations in thermodynamic MHD, with propagation out to 1 AU. We describe design features of the interface and computations, including the innovations required to efficiently compute results on practical timescales with moderate computational resources. CORHEL-CME is now implemented at NASA's Community Coordinated Modeling Center (CCMC) using NASA Amazon Web Services (AWS). It will be available to the public by the time this paper is published. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2311.03596v1-abstract-full').style.display = 'none'; document.getElementById('2311.03596v1-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> 6 November, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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, submitted to Journal of Physics Conference Series</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2310.02412">arXiv:2310.02412</a> <span> [<a href="https://arxiv.org/pdf/2310.02412">pdf</a>, <a href="https://arxiv.org/format/2310.02412">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"> Deflection of Coronal Mass Ejections in Unipolar Ambient Magnetic Fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Ben-Nun%2C+M">Michal Ben-Nun</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">Viacheslav S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Linton%2C+M+G">Mark G. Linton</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</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="2310.02412v1-abstract-short" style="display: inline;"> The trajectories of coronal mass ejections (CMEs) are often seen to substantially deviate from a purely radial propagation direction. Such deviations occur predominantly in the corona and have been attributed to "channeling" or deflection of the eruptive flux by asymmetric ambient magnetic fields. Here, we investigate an additional mechanism that does not require any asymmetry of the pre-eruptive… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.02412v1-abstract-full').style.display = 'inline'; document.getElementById('2310.02412v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2310.02412v1-abstract-full" style="display: none;"> The trajectories of coronal mass ejections (CMEs) are often seen to substantially deviate from a purely radial propagation direction. Such deviations occur predominantly in the corona and have been attributed to "channeling" or deflection of the eruptive flux by asymmetric ambient magnetic fields. Here, we investigate an additional mechanism that does not require any asymmetry of the pre-eruptive ambient field. Using magnetohydrodynamic numerical simulations, we show that the trajectory of CMEs through the solar corona can significantly deviate from a radial direction when propagation takes place in a unipolar radial field. We demonstrate that the deviation is most prominent below ~15 solar radii and can be attributed to an "effective IxB force" that arises from the intrusion of a magnetic flux rope with a net axial electric current into a unipolar background field. These results are important for predictions of CME trajectories in the context of space weather forecasts, as well as for reaching a deeper understanding of the fundamental physics underlying CME interactions with the ambient fields in the extended solar corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2310.02412v1-abstract-full').style.display = 'none'; document.getElementById('2310.02412v1-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">15 pages, 12 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/2309.11100">arXiv:2309.11100</a> <span> [<a href="https://arxiv.org/pdf/2309.11100">pdf</a>, <a href="https://arxiv.org/format/2309.11100">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/10.1051/0004-6361/202347180">10.1051/0004-6361/202347180 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> On the short term stability and tilting motion of a well-observed low-latitude solar coronal hole </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Heinemann%2C+S+G">Stephan G. Heinemann</a>, <a href="/search/astro-ph?searchtype=author&query=Hofmeister%2C+S+J">Stefan J. Hofmeister</a>, <a href="/search/astro-ph?searchtype=author&query=Turtle%2C+J+A">James A. Turtle</a>, <a href="/search/astro-ph?searchtype=author&query=Pomoell%2C+J">Jens Pomoell</a>, <a href="/search/astro-ph?searchtype=author&query=Asvestari%2C+E">Eleanna Asvestari</a>, <a href="/search/astro-ph?searchtype=author&query=Sterling%2C+A+C">Alphonse C. Sterling</a>, <a href="/search/astro-ph?searchtype=author&query=Diercke%2C+A">Andrea Diercke</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</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="2309.11100v1-abstract-short" style="display: inline;"> The understanding of the solar magnetic coronal structure is tightly linked to the shape of open field regions, specifically coronal holes. A dynamically evolving coronal hole coincides with the local restructuring of open to closed magnetic field, which leads to changes in the interplanetary solar wind structure. By investigating the dynamic evolution of a fast-tilting coronal hole, we strive to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.11100v1-abstract-full').style.display = 'inline'; document.getElementById('2309.11100v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.11100v1-abstract-full" style="display: none;"> The understanding of the solar magnetic coronal structure is tightly linked to the shape of open field regions, specifically coronal holes. A dynamically evolving coronal hole coincides with the local restructuring of open to closed magnetic field, which leads to changes in the interplanetary solar wind structure. By investigating the dynamic evolution of a fast-tilting coronal hole, we strive to uncover clues about what processes may drive its morphological changes, which are clearly visible in EUV filtergrams. Using combined 193A and 195A EUV observations by AIA/SDO and EUVI/STEREO_A, in conjunction with line-of-sight magnetograms taken by HMI/SDO, we track and analyze a coronal hole over 12 days to derive changes in morphology, area and magnetic field. We complement this analysis by potential field source surface modeling to compute the open field structure of the coronal hole. We find that the coronal hole exhibits an apparent tilting motion over time that cannot solely be explained by solar differential rotation. It tilts at a mean rate of ~3.2掳/day that accelerates up to ~5.4掳/day. At the beginning of May, the area of the coronal hole decreases by more than a factor of three over four days (from ~13 * 10^9 km^2 to ~4 * 10^9 km^2), but its open flux remains constant (~2 * 10^20 Mx). Further, the observed evolution is not reproduced by modeling that assumes the coronal magnetic field to be potential. In this study, we present a solar coronal hole that tilts at a rate that has yet to be reported in literature. The rate exceeds the effect of the coronal hole being advected by either photospheric or coronal differential rotation. Based on the analysis we find it likely that this is due to morphological changes in the coronal hole boundary caused by ongoing interchange reconnection and the interaction with a newly emerging ephemeral region in its vicinity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.11100v1-abstract-full').style.display = 'none'; document.getElementById('2309.11100v1-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 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 in A&A September 15, 2023; 10 pages, 8 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 679, A100 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.05480">arXiv:2309.05480</a> <span> [<a href="https://arxiv.org/pdf/2309.05480">pdf</a>, <a href="https://arxiv.org/format/2309.05480">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="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/10.3847/25c2cfeb.ba5ccef8">10.3847/25c2cfeb.ba5ccef8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> New Observations Needed to Advance Our Understanding of 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=Lynch%2C+B+J">Benjamin J. Lynch</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=Jian%2C+L+K">Lan K. Jian</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=Davies%2C+E+E">Emma E. Davies</a>, <a href="/search/astro-ph?searchtype=author&query=Wood%2C+B+E">Brian E. Wood</a>, <a href="/search/astro-ph?searchtype=author&query=Lugaz%2C+N">No茅 Lugaz</a>, <a href="/search/astro-ph?searchtype=author&query=Winslow%2C+R+M">R茅ka M. Winslow</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Al-Haddad%2C+N">Nada Al-Haddad</a>, <a href="/search/astro-ph?searchtype=author&query=Regnault%2C+F">Florian Regnault</a>, <a href="/search/astro-ph?searchtype=author&query=Jin%2C+M">Meng Jin</a>, <a href="/search/astro-ph?searchtype=author&query=Scolini%2C+C">Camilla Scolini</a>, <a href="/search/astro-ph?searchtype=author&query=Carcaboso%2C+F">Fernando Carcaboso</a>, <a href="/search/astro-ph?searchtype=author&query=Farrugia%2C+C+J">Charles J. Farrugia</a>, <a href="/search/astro-ph?searchtype=author&query=Ledvina%2C+V+E">Vincent E. Ledvina</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Kay%2C+C">Christina Kay</a>, <a href="/search/astro-ph?searchtype=author&query=Pal%2C+S">Sanchita Pal</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=Allen%2C+R+C">Robert C. Allen</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="2309.05480v1-abstract-short" style="display: inline;"> Coronal mass ejections (CMEs) are large eruptions from the Sun that propagate through the heliosphere after launch. Observational studies of these transient phenomena are usually based on 2D images of the Sun, corona, and heliosphere (remote-sensing data), as well as magnetic field, plasma, and particle samples along a 1D spacecraft trajectory (in-situ data). Given the large scales involved and th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.05480v1-abstract-full').style.display = 'inline'; document.getElementById('2309.05480v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.05480v1-abstract-full" style="display: none;"> Coronal mass ejections (CMEs) are large eruptions from the Sun that propagate through the heliosphere after launch. Observational studies of these transient phenomena are usually based on 2D images of the Sun, corona, and heliosphere (remote-sensing data), as well as magnetic field, plasma, and particle samples along a 1D spacecraft trajectory (in-situ data). Given the large scales involved and the 3D nature of CMEs, such measurements are generally insufficient to build a comprehensive picture, especially in terms of local variations and overall geometry of the whole structure. This White Paper aims to address this issue by identifying the data sets and observational priorities that are needed to effectively advance our current understanding of the structure and evolution of CMEs, in both the remote-sensing and in-situ regimes. It also provides an outlook of possible missions and instruments that may yield significant improvements into the subject. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.05480v1-abstract-full').style.display = 'none'; document.getElementById('2309.05480v1-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> 11 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">White Paper submitted to the Heliophysics 2024-2033 Decadal Survey, 9 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Bulletin of the AAS, 55(3), 307, 2023 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.12551">arXiv:2306.12551</a> <span> [<a href="https://arxiv.org/pdf/2306.12551">pdf</a>, <a href="https://arxiv.org/format/2306.12551">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"> Global MHD Simulations of the Time-Dependent Corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+E+I">Emily I. Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">Pete Riley</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">Viacheslav S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=DeRosa%2C+M+L">Marc L. DeRosa</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="2306.12551v4-abstract-short" style="display: inline;"> We describe, test, and apply a technique to incorporate full-sun, surface flux evolution into an MHD model of the global solar corona. Requiring only maps of the evolving surface flux, our method is similar to that of Lionello et al. (2013), but we introduce two ways to correct the electric field at the lower boundary to mitigate spurious currents. We verify the accuracy of our procedures by compa… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.12551v4-abstract-full').style.display = 'inline'; document.getElementById('2306.12551v4-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.12551v4-abstract-full" style="display: none;"> We describe, test, and apply a technique to incorporate full-sun, surface flux evolution into an MHD model of the global solar corona. Requiring only maps of the evolving surface flux, our method is similar to that of Lionello et al. (2013), but we introduce two ways to correct the electric field at the lower boundary to mitigate spurious currents. We verify the accuracy of our procedures by comparing to a reference simulation, driven with known flows and electric fields. We then present a thermodynamic MHD calculation lasting one solar rotation driven by maps from the magnetic flux evolution model of Schrijver & DeRosa (2003). The dynamic, time-dependent nature of the model corona is illustrated by examining the evolution of the open flux boundaries and forward modeled EUV emission, which evolve in response to surface flows and the emergence and cancellation flux. Although our main goal is to present the method, we briefly investigate the relevance of this evolution to properties of the slow solar wind, examining the mapping of dipped field lines to the topological signatures of the "S-Web" and comparing charge state ratios computed in the time-dependently driven run to a steady state equivalent. Interestingly, we find that driving on its own does not significantly improve the charge states ratios, at least in this modest resolution run that injects minimal helicity. Still, many aspects of the time-dependently driven model cannot be captured with traditional steady-state methods, and such a technique may be particularly relevant for the next generation of solar wind and CME models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.12551v4-abstract-full').style.display = 'none'; document.getElementById('2306.12551v4-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 October, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 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 for publication on 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/2306.11956">arXiv:2306.11956</a> <span> [<a href="https://arxiv.org/pdf/2306.11956">pdf</a>, <a href="https://arxiv.org/format/2306.11956">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"> Time-Dependent Dynamics of the Corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mason%2C+E+I">Emily I. Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</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="2306.11956v1-abstract-short" style="display: inline;"> We present in this Letter the first global comparison between traditional line-tied steady state magnetohydrodynamic models and a new, fully time-dependent thermodynamic magnetohydrodynamic simulation of the global corona. The maps are scaled to the approximate field distributions and magnitudes around solar minimum using the Lockheed Evolving Surface-Flux Assimilation Model to incorporate flux em… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.11956v1-abstract-full').style.display = 'inline'; document.getElementById('2306.11956v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.11956v1-abstract-full" style="display: none;"> We present in this Letter the first global comparison between traditional line-tied steady state magnetohydrodynamic models and a new, fully time-dependent thermodynamic magnetohydrodynamic simulation of the global corona. The maps are scaled to the approximate field distributions and magnitudes around solar minimum using the Lockheed Evolving Surface-Flux Assimilation Model to incorporate flux emergence and surface flows over a full solar rotation, and include differential rotation and meridional flows. Each time step evolves the previous state of the plasma with a new magnetic field input boundary condition. We find that this method is a significant improvement over steady-state models, as it closely mimics the constant photospheric driving on the Sun. The magnetic energy levels are higher in the time-dependent model, and coronal holes evolve more along the following edge than they do in steady-state models. Coronal changes, as illustrated with forward-modeled emission maps, evolve on longer timescales with time-dependent driving. We discuss implications for active and quiet Sun scenarios, solar wind formation, and widely-used steady state assumptions like potential field source surface calculations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.11956v1-abstract-full').style.display = 'none'; document.getElementById('2306.11956v1-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 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">9 pages, 4 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/2306.10819">arXiv:2306.10819</a> <span> [<a href="https://arxiv.org/pdf/2306.10819">pdf</a>, <a href="https://arxiv.org/format/2306.10819">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"> Coronal Heating Rate in the Slow Solar Wind </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=Romoli%2C+M">Marco Romoli</a>, <a href="/search/astro-ph?searchtype=author&query=Velli%2C+M">Marco Velli</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=Adhikari%2C+L">Laxman Adhikari</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Burtovoi%2C+A">Aleksandr Burtovoi</a>, <a href="/search/astro-ph?searchtype=author&query=Susino%2C+R">Roberto Susino</a>, <a href="/search/astro-ph?searchtype=author&query=Spadaro%2C+D">Daniele Spadaro</a>, <a href="/search/astro-ph?searchtype=author&query=Zhao%2C+L">Lingling Zhao</a>, <a href="/search/astro-ph?searchtype=author&query=Liberatore%2C+A">Alessandro Liberatore</a>, <a href="/search/astro-ph?searchtype=author&query=Shi%2C+C">Chen Shi</a>, <a href="/search/astro-ph?searchtype=author&query=De+Leo%2C+Y">Yara De Leo</a>, <a href="/search/astro-ph?searchtype=author&query=Abbo%2C+L">Lucia Abbo</a>, <a href="/search/astro-ph?searchtype=author&query=Frassati%2C+F">Federica Frassati</a>, <a href="/search/astro-ph?searchtype=author&query=Jerse%2C+G">Giovanna Jerse</a>, <a href="/search/astro-ph?searchtype=author&query=Landini%2C+F">Federico Landini</a>, <a href="/search/astro-ph?searchtype=author&query=Nicolini%2C+G">Gianalfredo Nicolini</a>, <a href="/search/astro-ph?searchtype=author&query=Pancrazzi%2C+M">Maurizio Pancrazzi</a>, <a href="/search/astro-ph?searchtype=author&query=Russano%2C+G">Giuliana Russano</a>, <a href="/search/astro-ph?searchtype=author&query=Sasso%2C+C">Clementina Sasso</a>, <a href="/search/astro-ph?searchtype=author&query=Andretta%2C+V">Vincenzo Andretta</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=Grimani%2C+C">Catia Grimani</a> , et al. (37 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="2306.10819v1-abstract-short" style="display: inline;"> This Letter reports the first observational estimate of the heating rate in the slowly expanding solar corona. The analysis exploits the simultaneous remote and local observations of the same coronal plasma volume with the Solar Orbiter/Metis and the Parker Solar Probe instruments, respectively, and relies on the basic solar wind magnetohydrodynamic equations. As expected, energy losses are a mino… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.10819v1-abstract-full').style.display = 'inline'; document.getElementById('2306.10819v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.10819v1-abstract-full" style="display: none;"> This Letter reports the first observational estimate of the heating rate in the slowly expanding solar corona. The analysis exploits the simultaneous remote and local observations of the same coronal plasma volume with the Solar Orbiter/Metis and the Parker Solar Probe instruments, respectively, and relies on the basic solar wind magnetohydrodynamic equations. As expected, energy losses are a minor fraction of the solar wind energy flux, since most of the energy dissipation that feeds the heating and acceleration of the coronal flow occurs much closer to the Sun than the heights probed in the present study, which range from 6.3 to 13.3 solar radii. The energy deposited to the supersonic wind is then used to explain the observed slight residual wind acceleration and to maintain the plasma in a non-adiabatic state. As derived in the Wentzel-Kramers-Brillouin limit, the present energy transfer rate estimates provide a lower limit, which can be very useful in refining the turbulence-based modeling of coronal heating and subsequent solar wind acceleration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.10819v1-abstract-full').style.display = 'none'; document.getElementById('2306.10819v1-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 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.05444">arXiv:2306.05444</a> <span> [<a href="https://arxiv.org/pdf/2306.05444">pdf</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="Physics and Society">physics.soc-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/10.3847/25c2cfeb.007ec3a4">10.3847/25c2cfeb.007ec3a4 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Work-Life Balance Starts with Proper Deadlines and Exemplary Agencies </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lugaz%2C+N">No茅 Lugaz</a>, <a href="/search/astro-ph?searchtype=author&query=Winslow%2C+R+M">R茅ka M. Winslow</a>, <a href="/search/astro-ph?searchtype=author&query=Al-Haddad%2C+N">Nada Al-Haddad</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=Vines%2C+S+K">Sarah K. Vines</a>, <a href="/search/astro-ph?searchtype=author&query=Reeves%2C+K">Katharine Reeves</a>, <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">Daniel Seaton</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Glesener%2C+L">Lindsay Glesener</a>, <a href="/search/astro-ph?searchtype=author&query=Vourlidas%2C+A">Angelos Vourlidas</a>, <a href="/search/astro-ph?searchtype=author&query=Scolini%2C+C">Camilla Scolini</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Allen%2C+R">Robert Allen</a>, <a href="/search/astro-ph?searchtype=author&query=Palmerio%2C+E">Erika Palmerio</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="2306.05444v1-abstract-short" style="display: inline;"> Diversity, equity and inclusion (DEI) programs can only be implemented successfully if proper work-life balance is possible in Heliophysics (and in STEM field in general). One of the core issues stems from the culture of "work-above-life" associated with mission concepts, development, and implementation but also the expectations that seem to originate from numerous announcements from NASA (and oth… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.05444v1-abstract-full').style.display = 'inline'; document.getElementById('2306.05444v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.05444v1-abstract-full" style="display: none;"> Diversity, equity and inclusion (DEI) programs can only be implemented successfully if proper work-life balance is possible in Heliophysics (and in STEM field in general). One of the core issues stems from the culture of "work-above-life" associated with mission concepts, development, and implementation but also the expectations that seem to originate from numerous announcements from NASA (and other agencies). The benefits of work-life balance are well documented; however, the entire system surrounding research in Heliophysics hinders or discourages proper work-life balance. For example, there does not seem to be attention paid by NASA Headquarters (HQ) on the timing of their announcements regarding how it will be perceived by researchers, and how the timing may promote a culture where work trumps personal life. The same is true for remarks by NASA HQ program officers during panels or informal discussions, where seemingly innocuous comments may give a perception that work is expected after "normal" work hours. In addition, we are calling for work-life balance plans and implementation to be one of the criteria used for down-selection and confirmation of missions (Key Decision Points: KDP-B, KDP-C). <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.05444v1-abstract-full').style.display = 'none'; document.getElementById('2306.05444v1-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">White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 6 pages</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Bulletin of the AAS, Vol. 55, Issue 3, Whitepaper #250 (6pp); 2023 July 31 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2306.04826">arXiv:2306.04826</a> <span> [<a href="https://arxiv.org/pdf/2306.04826">pdf</a>, <a href="https://arxiv.org/format/2306.04826">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/acd10b">10.3847/1538-4357/acd10b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Solar Minimum Eclipse of 2019 July 2. III. Inferring the Coronal $T_e$ with a Radiative Differential Emission Measure Inversion </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Boe%2C+B">Benjamin Boe</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Habbal%2C+S">Shadia Habbal</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="2306.04826v1-abstract-short" style="display: inline;"> Differential Emission Measure (DEM) inversion methods use the brightness of a set of emission lines to infer the line-of-sight (LOS) distribution of the electron temperature ($T_e$) in the corona. DEM inversions have been traditionally performed with collisionally excited lines at wavelengths in the Extreme Ultraviolet (EUV) and X-ray. However, such emission is difficult to observe beyond the inne… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.04826v1-abstract-full').style.display = 'inline'; document.getElementById('2306.04826v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2306.04826v1-abstract-full" style="display: none;"> Differential Emission Measure (DEM) inversion methods use the brightness of a set of emission lines to infer the line-of-sight (LOS) distribution of the electron temperature ($T_e$) in the corona. DEM inversions have been traditionally performed with collisionally excited lines at wavelengths in the Extreme Ultraviolet (EUV) and X-ray. However, such emission is difficult to observe beyond the inner corona (1.5 R$_\odot$), particularly in coronal holes. Given the importance of the $T_e$ distribution in the corona for exploring the viability of different heating processes, we introduce an analog of the DEM specifically for radiatively excited coronal emission lines, such as those observed during total solar eclipses (TSEs) and with coronagraphs. This Radiative DEM (R-DEM) inversion utilizes visible and infrared emission lines which are excited by photospheric radiation out to at least 3 R$_\odot$. Specifically, we use the Fe X (637 nm), Fe XI (789 nm), and Fe XIV (530 nm) coronal emission lines observed during the 2019 July 2 TSE near solar minimum. We find that despite a large $T_e$ spread in the inner corona, the distribution converges to an almost isothermal yet bimodal distribution beyond 1.4 R$_\odot$, with $T_e$ ranging from 1.1 to 1.4 in coronal holes, and from 1.4 to 1.65 MK in quiescent streamers. Application of the R-DEM inversion to the Predictive Science Inc. magnetohydrodynamic (MHD) simulation for the 2019 eclipse validates the R-DEM method and yields a similar LOS Te distribution to the eclipse data. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2306.04826v1-abstract-full').style.display = 'none'; document.getElementById('2306.04826v1-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 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">20 pages, 9 figures, accepted for publication 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/2305.17146">arXiv:2305.17146</a> <span> [<a href="https://arxiv.org/pdf/2305.17146">pdf</a>, <a href="https://arxiv.org/format/2305.17146">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="High Energy Astrophysical Phenomena">astro-ph.HE</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/10.3847/25c2cfeb.1dbfea1f">10.3847/25c2cfeb.1dbfea1f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Magnetic Energy Powers the Corona: How We Can Understand its 3D Storage & Release </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=Casini%2C+R">Roberto Casini</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Gibson%2C+S+E">Sarah E. Gibson</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+H">Holly Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Glesener%2C+L">Lindsay Glesener</a>, <a href="/search/astro-ph?searchtype=author&query=Guidoni%2C+S+E">Silvina E. Guidoni</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+J+M">J. Marcus Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=McKenzie%2C+D">David McKenzie</a>, <a href="/search/astro-ph?searchtype=author&query=Plowman%2C+J">Joseph Plowman</a>, <a href="/search/astro-ph?searchtype=author&query=Reeves%2C+K+K">Katharine K. Reeves</a>, <a href="/search/astro-ph?searchtype=author&query=Saint-Hilaire%2C+P">Pascal Saint-Hilaire</a>, <a href="/search/astro-ph?searchtype=author&query=Shih%2C+A+Y">Albert Y. Shih</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">Matthew J. West</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="2305.17146v1-abstract-short" style="display: inline;"> The coronal magnetic field is the prime driver behind many as-yet unsolved mysteries: solar eruptions, coronal heating, and the solar wind, to name a few. It is, however, still poorly observed and understood. We highlight key questions related to magnetic energy storage, release, and transport in the solar corona, and their relationship to these important problems. We advocate for new and multi-po… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.17146v1-abstract-full').style.display = 'inline'; document.getElementById('2305.17146v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.17146v1-abstract-full" style="display: none;"> The coronal magnetic field is the prime driver behind many as-yet unsolved mysteries: solar eruptions, coronal heating, and the solar wind, to name a few. It is, however, still poorly observed and understood. We highlight key questions related to magnetic energy storage, release, and transport in the solar corona, and their relationship to these important problems. We advocate for new and multi-point co-optimized measurements, sensitive to magnetic field and other plasma parameters, spanning from optical to $纬$-ray wavelengths, to bring closure to these long-standing and fundamental questions. We discuss how our approach can fully describe the 3D magnetic field, embedded plasma, particle energization, and their joint evolution to achieve these objectives. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.17146v1-abstract-full').style.display = 'none'; document.getElementById('2305.17146v1-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 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">White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 16 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Bulletin of the AAS, Vol. 55, Issue 3, Whitepaper #049 (16pp); 2023 July 31 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.16535">arXiv:2305.16535</a> <span> [<a href="https://arxiv.org/pdf/2305.16535">pdf</a>, <a href="https://arxiv.org/format/2305.16535">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="Data Analysis, Statistics and Probability">physics.data-an</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/10.3847/25c2cfeb.6d8ecdc1">10.3847/25c2cfeb.6d8ecdc1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Improving Multi-Dimensional Data Formats, Access, and Assimilation Tools for the Twenty-First Century </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Seaton%2C+D+B">Daniel B. Seaton</a>, <a href="/search/astro-ph?searchtype=author&query=Caspi%2C+A">Amir Caspi</a>, <a href="/search/astro-ph?searchtype=author&query=Casini%2C+R">Roberto Casini</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Gibson%2C+S+E">Sarah E. Gibson</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+H">Holly Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Glesener%2C+L">Lindsay Glesener</a>, <a href="/search/astro-ph?searchtype=author&query=Guidoni%2C+S+E">Silvina E. Guidoni</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+J+M">J. Marcus Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=McKenzie%2C+D">David McKenzie</a>, <a href="/search/astro-ph?searchtype=author&query=Plowman%2C+J">Joseph Plowman</a>, <a href="/search/astro-ph?searchtype=author&query=Reeves%2C+K+K">Katharine K. Reeves</a>, <a href="/search/astro-ph?searchtype=author&query=Saint-Hilaire%2C+P">Pascal Saint-Hilaire</a>, <a href="/search/astro-ph?searchtype=author&query=Shih%2C+A+Y">Albert Y. Shih</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">Matthew J. West</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="2305.16535v1-abstract-short" style="display: inline;"> Heliophysics image data largely relies on a forty-year-old ecosystem built on the venerable Flexible Image Transport System (FITS) data standard. While many in situ measurements use newer standards, they are difficult to integrate with multiple data streams required to develop global understanding. Additionally, most data users still engage with data in much the same way as they did decades ago. H… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.16535v1-abstract-full').style.display = 'inline'; document.getElementById('2305.16535v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.16535v1-abstract-full" style="display: none;"> Heliophysics image data largely relies on a forty-year-old ecosystem built on the venerable Flexible Image Transport System (FITS) data standard. While many in situ measurements use newer standards, they are difficult to integrate with multiple data streams required to develop global understanding. Additionally, most data users still engage with data in much the same way as they did decades ago. However, contemporary missions and models require much more complex support for 3D multi-parameter data, robust data assimilation strategies, and integration of multiple individual data streams required to derive complete physical characterizations of the Sun and Heliospheric plasma environment. In this white paper we highlight some of the 21$^\mathsf{st}$ century challenges for data frameworks in heliophysics, consider an illustrative case study, and make recommendations for important steps the field can take to modernize its data products and data usage models. Our specific recommendations include: (1) Investing in data assimilation capability to drive advanced data-constrained models, (2) Investing in new strategies for integrating data across multiple instruments to realize measurements that cannot be produced from single observations, (3) Rethinking old data use paradigms to improve user access, develop deep understanding, and decrease barrier to entry for new datasets, and (4) Investing in research on data formats better suited for multi-dimensional data and cloud-based computing. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.16535v1-abstract-full').style.display = 'none'; document.getElementById('2305.16535v1-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 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">White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 9 pages, 3 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Bulletin of the AAS, Vol. 55, Issue 3, Whitepaper #361 (9pp); 2023 July 31 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2305.16533">arXiv:2305.16533</a> <span> [<a href="https://arxiv.org/pdf/2305.16533">pdf</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="High Energy Astrophysical Phenomena">astro-ph.HE</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/10.3847/25c2cfeb.b95dd671">10.3847/25c2cfeb.b95dd671 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> COMPLETE: A flagship mission for complete understanding of 3D coronal magnetic energy release </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=Casini%2C+R">Roberto Casini</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Gibson%2C+S+E">Sarah E. Gibson</a>, <a href="/search/astro-ph?searchtype=author&query=Gilbert%2C+H">Holly Gilbert</a>, <a href="/search/astro-ph?searchtype=author&query=Glesener%2C+L">Lindsay Glesener</a>, <a href="/search/astro-ph?searchtype=author&query=Guidoni%2C+S+E">Silvina E. Guidoni</a>, <a href="/search/astro-ph?searchtype=author&query=Hughes%2C+J+M">J. Marcus Hughes</a>, <a href="/search/astro-ph?searchtype=author&query=McKenzie%2C+D">David McKenzie</a>, <a href="/search/astro-ph?searchtype=author&query=Plowman%2C+J">Joseph Plowman</a>, <a href="/search/astro-ph?searchtype=author&query=Reeves%2C+K+K">Katharine K. Reeves</a>, <a href="/search/astro-ph?searchtype=author&query=Saint-Hilaire%2C+P">Pascal Saint-Hilaire</a>, <a href="/search/astro-ph?searchtype=author&query=Shih%2C+A+Y">Albert Y. Shih</a>, <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">Matthew J. West</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="2305.16533v1-abstract-short" style="display: inline;"> COMPLETE is a flagship mission concept combining broadband spectroscopic imaging and comprehensive magnetography from multiple viewpoints around the Sun to enable tomographic reconstruction of 3D coronal magnetic fields and associated dynamic plasma properties, which provide direct diagnostics of energy release. COMPLETE re-imagines the paradigm for solar remote-sensing observations through purpos… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.16533v1-abstract-full').style.display = 'inline'; document.getElementById('2305.16533v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2305.16533v1-abstract-full" style="display: none;"> COMPLETE is a flagship mission concept combining broadband spectroscopic imaging and comprehensive magnetography from multiple viewpoints around the Sun to enable tomographic reconstruction of 3D coronal magnetic fields and associated dynamic plasma properties, which provide direct diagnostics of energy release. COMPLETE re-imagines the paradigm for solar remote-sensing observations through purposefully co-optimized detectors distributed on multiple spacecraft that operate as a single observatory, linked by a comprehensive data/model assimilation strategy to unify individual observations into a single physical framework. We describe COMPLETE's science goals, instruments, and mission implementation. With targeted investment by NASA, COMPLETE is feasible for launch in 2032 to observe around the maximum of Solar Cycle 26. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2305.16533v1-abstract-full').style.display = 'none'; document.getElementById('2305.16533v1-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 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">White paper submitted to the Decadal Survey for Solar and Space Physics (Heliophysics) 2024-2033; 10 pages, 6 figures, 1 table</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Bulletin of the AAS, Vol. 55, Issue 3, Whitepaper #048 (10pp); 2023 July 31 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.08385">arXiv:2302.08385</a> <span> [<a href="https://arxiv.org/pdf/2302.08385">pdf</a>, <a href="https://arxiv.org/format/2302.08385">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/10.1063/5.0132824">10.1063/5.0132824 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Slow wind belt in the quiet solar corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Antonucci%2C+E">E. Antonucci</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Capuano%2C+G+E">G. E. Capuano</a>, <a href="/search/astro-ph?searchtype=author&query=Spadaro%2C+D">D. Spadaro</a>, <a href="/search/astro-ph?searchtype=author&query=Susino%2C+R">R. Susino</a>, <a href="/search/astro-ph?searchtype=author&query=Telloni%2C+D">D. Telloni</a>, <a href="/search/astro-ph?searchtype=author&query=Andretta%2C+V">V. Andretta</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=De+Leo%2C+Y">Y. De Leo</a>, <a href="/search/astro-ph?searchtype=author&query=Fineschi%2C+S">S. Fineschi</a>, <a href="/search/astro-ph?searchtype=author&query=Frassetto%2C+F">F. Frassetto</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>, <a href="/search/astro-ph?searchtype=author&query=Stangalini%2C+M">M. Stangalini</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Uslenghi%2C+M">M. Uslenghi</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="2302.08385v1-abstract-short" style="display: inline;"> The slow solar wind belt in the quiet corona, observed with the Metis coronagraph on board Solar Orbiter on May 15, 2020, during the activity minimum of the cycle 24, in a field of view extending from 3.8 $R_\odot$ to 7.0 $R_\odot$, is formed by a slow and dense wind stream running along the coronal current sheet, accelerating in the radial direction and reaching at 6.8 $R_\odot$ a speed within 15… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.08385v1-abstract-full').style.display = 'inline'; document.getElementById('2302.08385v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.08385v1-abstract-full" style="display: none;"> The slow solar wind belt in the quiet corona, observed with the Metis coronagraph on board Solar Orbiter on May 15, 2020, during the activity minimum of the cycle 24, in a field of view extending from 3.8 $R_\odot$ to 7.0 $R_\odot$, is formed by a slow and dense wind stream running along the coronal current sheet, accelerating in the radial direction and reaching at 6.8 $R_\odot$ a speed within 150 km s$^{-1}$ and 190 km s$^{-1}$, depending on the assumptions on the velocity distribution of the neutral hydrogen atoms in the coronal plasma. The slow stream is separated by thin regions of high velocity shear from faster streams, almost symmetric relative to the current sheet, with peak velocity within 175 km s$^{-1}$ and 230 km s$^{-1}$ at the same coronal level. The density-velocity structure of the slow wind zone is discussed in terms of the expansion factor of the open magnetic field lines that is known to be related to the speed of the quasi-steady solar wind, and in relation to the presence of a web of quasi separatrix layers, S-web, the potential sites of reconnection that release coronal plasma into the wind. The parameters characterizing the coronal magnetic field lines are derived from 3D MHD model calculations. The S-web is found to coincide with the latitudinal region where the slow wind is observed in the outer corona and is surrounded by thin layers of open field lines expanding in a non-monotonic way. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.08385v1-abstract-full').style.display = 'none'; document.getElementById('2302.08385v1-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 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2301.07647">arXiv:2301.07647</a> <span> [<a href="https://arxiv.org/pdf/2301.07647">pdf</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> <p class="title is-5 mathjax"> Solaris: A Focused Solar Polar Discovery-class Mission to achieve the Highest Priority Heliophysics Science Now </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Hassler%2C+D+M">Donald M. Hassler</a>, <a href="/search/astro-ph?searchtype=author&query=Gibson%2C+S+E">Sarah E Gibson</a>, <a href="/search/astro-ph?searchtype=author&query=Newmark%2C+J+S">Jeffrey S Newmark</a>, <a href="/search/astro-ph?searchtype=author&query=Featherstone%2C+N+A">Nicholas A. Featherstone</a>, <a href="/search/astro-ph?searchtype=author&query=Upton%2C+L">Lisa Upton</a>, <a href="/search/astro-ph?searchtype=author&query=Viall%2C+N+M">Nicholeen M Viall</a>, <a href="/search/astro-ph?searchtype=author&query=Hoeksema%2C+J+T">J Todd Hoeksema</a>, <a href="/search/astro-ph?searchtype=author&query=Auchere%2C+F">Frederic Auchere</a>, <a href="/search/astro-ph?searchtype=author&query=Birch%2C+A">Aaron Birch</a>, <a href="/search/astro-ph?searchtype=author&query=Braun%2C+D">Doug Braun</a>, <a href="/search/astro-ph?searchtype=author&query=Charbonneau%2C+P">Paul Charbonneau</a>, <a href="/search/astro-ph?searchtype=author&query=Colannino%2C+R">Robin Colannino</a>, <a href="/search/astro-ph?searchtype=author&query=DeForest%2C+C">Craig DeForest</a>, <a href="/search/astro-ph?searchtype=author&query=Dikpati%2C+M">Mausumi Dikpati</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Duncan%2C+N">Nicole Duncan</a>, <a href="/search/astro-ph?searchtype=author&query=Elliott%2C+H+A">Heather Alison Elliott</a>, <a href="/search/astro-ph?searchtype=author&query=Fan%2C+Y">Yuhong Fan</a>, <a href="/search/astro-ph?searchtype=author&query=Fineschi%2C+S">Silvano Fineschi</a>, <a href="/search/astro-ph?searchtype=author&query=Gizon%2C+L">Laurent Gizon</a>, <a href="/search/astro-ph?searchtype=author&query=Gosain%2C+S">Sanjay Gosain</a>, <a href="/search/astro-ph?searchtype=author&query=Harra%2C+L">Louise Harra</a>, <a href="/search/astro-ph?searchtype=author&query=Hindman%2C+B">Brad Hindman</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Lepri%2C+S+T">Susan T Lepri</a> , et al. (11 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="2301.07647v1-abstract-short" style="display: inline;"> Solaris is a transformative Solar Polar Discovery-class mission concept to address crucial outstanding questions that can only be answered from a polar vantage. Solaris will image the Sun's poles from ~75 degree latitude, providing new insight into the workings of the solar dynamo and the solar cycle, which are at the foundation of our understanding of space weather and space climate. Solaris will… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.07647v1-abstract-full').style.display = 'inline'; document.getElementById('2301.07647v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.07647v1-abstract-full" style="display: none;"> Solaris is a transformative Solar Polar Discovery-class mission concept to address crucial outstanding questions that can only be answered from a polar vantage. Solaris will image the Sun's poles from ~75 degree latitude, providing new insight into the workings of the solar dynamo and the solar cycle, which are at the foundation of our understanding of space weather and space climate. Solaris will also provide enabling observations for improved space weather research, modeling and prediction, revealing a unique, new view of the corona, coronal dynamics and CME eruptions from above. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.07647v1-abstract-full').style.display = 'none'; document.getElementById('2301.07647v1-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 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">This White Paper was submitted in 2022 to the United States National Academies Solar and Space Physics (Heliophysics) Decadal Survey</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.14879">arXiv:2211.14879</a> <span> [<a href="https://arxiv.org/pdf/2211.14879">pdf</a>, <a href="https://arxiv.org/format/2211.14879">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> <p class="title is-5 mathjax"> SuNeRF: Validation of a 3D Global Reconstruction of the Solar Corona Using Simulated EUV Images </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Bintsi%2C+K">Kyriaki-Margarita Bintsi</a>, <a href="/search/astro-ph?searchtype=author&query=Jarolim%2C+R">Robert Jarolim</a>, <a href="/search/astro-ph?searchtype=author&query=Tremblay%2C+B">Benoit Tremblay</a>, <a href="/search/astro-ph?searchtype=author&query=Santos%2C+M">Miraflor Santos</a>, <a href="/search/astro-ph?searchtype=author&query=Jungbluth%2C+A">Anna Jungbluth</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+J+P">James Paul Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Sundaresan%2C+S">Sairam Sundaresan</a>, <a href="/search/astro-ph?searchtype=author&query=Vourlidas%2C+A">Angelos Vourlidas</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Jaramillo%2C+A+M">Andr茅s Mu帽oz Jaramillo</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="2211.14879v1-abstract-short" style="display: inline;"> Extreme Ultraviolet (EUV) light emitted by the Sun impacts satellite operations and communications and affects the habitability of planets. Currently, EUV-observing instruments are constrained to viewing the Sun from its equator (i.e., ecliptic), limiting our ability to forecast EUV emission for other viewpoints (e.g. solar poles), and to generalize our knowledge of the Sun-Earth system to other h… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.14879v1-abstract-full').style.display = 'inline'; document.getElementById('2211.14879v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.14879v1-abstract-full" style="display: none;"> Extreme Ultraviolet (EUV) light emitted by the Sun impacts satellite operations and communications and affects the habitability of planets. Currently, EUV-observing instruments are constrained to viewing the Sun from its equator (i.e., ecliptic), limiting our ability to forecast EUV emission for other viewpoints (e.g. solar poles), and to generalize our knowledge of the Sun-Earth system to other host stars. In this work, we adapt Neural Radiance Fields (NeRFs) to the physical properties of the Sun and demonstrate that non-ecliptic viewpoints could be reconstructed from observations limited to the solar ecliptic. To validate our approach, we train on simulations of solar EUV emission that provide a ground truth for all viewpoints. Our model accurately reconstructs the simulated 3D structure of the Sun, achieving a peak signal-to-noise ratio of 43.3 dB and a mean absolute relative error of 0.3\% for non-ecliptic viewpoints. Our method provides a consistent 3D reconstruction of the Sun from a limited number of viewpoints, thus highlighting the potential to create a virtual instrument for satellite observations of the Sun. Its extension to real observations will provide the missing link to compare the Sun to other stars and to improve space-weather forecasting. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.14879v1-abstract-full').style.display = 'none'; document.getElementById('2211.14879v1-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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 at Machine Learning and the Physical Sciences workshop, NeurIPS 2022</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2211.13283">arXiv:2211.13283</a> <span> [<a href="https://arxiv.org/pdf/2211.13283">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/10.1038/s41550-022-01834-5">10.1038/s41550-022-01834-5 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Direct observations of a complex coronal web driving highly structured 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=Seaton%2C+D+B">D. B. Seaton</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=DeForest%2C+C+E">C. E. DeForest</a>, <a href="/search/astro-ph?searchtype=author&query=Higginson%2C+A+K">A. K. Higginson</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="2211.13283v1-abstract-short" style="display: inline;"> The solar wind consists of continuous streams of charged particles that escape into the heliosphere from the Sun, and is split into fast and slow components, with the fast wind emerging from the interiors of coronal holes. Near the ecliptic plane, the fast wind from low-latitude coronal holes is interspersed with a highly structured slow solar wind, the source regions and drivers of which are poor… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13283v1-abstract-full').style.display = 'inline'; document.getElementById('2211.13283v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2211.13283v1-abstract-full" style="display: none;"> The solar wind consists of continuous streams of charged particles that escape into the heliosphere from the Sun, and is split into fast and slow components, with the fast wind emerging from the interiors of coronal holes. Near the ecliptic plane, the fast wind from low-latitude coronal holes is interspersed with a highly structured slow solar wind, the source regions and drivers of which are poorly understood. Here we report extreme-ultraviolet observations that reveal a spatially complex web of magnetized plasma structures that persistently interact and reconnect in the middle corona. Coronagraphic white-light images show concurrent emergence of slow wind streams over these coronal web structures. With advanced global MHD coronal models, we demonstrate that the observed coronal web is a direct imprint of the magnetic separatrix web (S-web). By revealing a highly dynamic portion of the S-web, our observations open a window into important middle-coronal processes that appear to play a key role in driving the structured slow solar wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2211.13283v1-abstract-full').style.display = 'none'; document.getElementById('2211.13283v1-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 November, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">This version of the article has been accepted for publication, after peer review but is not the Version of Record and does not reflect post-acceptance improvements, or any corrections. The Version of Record is available online at: http://dx.doi.org/10.1038/s41550-022-01834-5</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2209.03611">arXiv:2209.03611</a> <span> [<a href="https://arxiv.org/pdf/2209.03611">pdf</a>, <a href="https://arxiv.org/format/2209.03611">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> <p class="title is-5 mathjax"> Advancing Theory and Modeling Efforts in Heliophysics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Guo%2C+F">Fan Guo</a>, <a href="/search/astro-ph?searchtype=author&query=Antiochos%2C+S">Spiro Antiochos</a>, <a href="/search/astro-ph?searchtype=author&query=Cassak%2C+P">Paul Cassak</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+B">Bin Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+X">Xiaohang Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Dong%2C+C">Chuanfei Dong</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Giacalone%2C+J">Joe Giacalone</a>, <a href="/search/astro-ph?searchtype=author&query=Haggerty%2C+C+C">Colby C. Haggerty</a>, <a href="/search/astro-ph?searchtype=author&query=Ji%2C+H">Hantao Ji</a>, <a href="/search/astro-ph?searchtype=author&query=Karpen%2C+J">Judith Karpen</a>, <a href="/search/astro-ph?searchtype=author&query=Klimchuk%2C+J">James Klimchuk</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+W">Wen Li</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+X">Xiaocan Li</a>, <a href="/search/astro-ph?searchtype=author&query=Oka%2C+M">Mitsuo Oka</a>, <a href="/search/astro-ph?searchtype=author&query=Reeves%2C+K+K">Katharine K. Reeves</a>, <a href="/search/astro-ph?searchtype=author&query=Swisdak%2C+M">Marc Swisdak</a>, <a href="/search/astro-ph?searchtype=author&query=Tu%2C+W">Weichao Tu</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="2209.03611v1-abstract-short" style="display: inline;"> Heliophysics theory and modeling build understanding from fundamental principles to motivate, interpret, and predict observations. Together with observational analysis, they constitute a comprehensive scientific program in heliophysics. As observations and data analysis become increasingly detailed, it is critical that theory and modeling develop more quantitative predictions and iterate with obse… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.03611v1-abstract-full').style.display = 'inline'; document.getElementById('2209.03611v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2209.03611v1-abstract-full" style="display: none;"> Heliophysics theory and modeling build understanding from fundamental principles to motivate, interpret, and predict observations. Together with observational analysis, they constitute a comprehensive scientific program in heliophysics. As observations and data analysis become increasingly detailed, it is critical that theory and modeling develop more quantitative predictions and iterate with observations. Advanced theory and modeling can inspire and greatly improve the design of new instruments and increase their chance of success. In addition, in order to build physics-based space weather forecast models, it is important to keep developing and testing new theories, and maintaining constant communications with theory and modeling. Maintaining a sustainable effort in theory and modeling is critically important to heliophysics. We recommend that all funding agencies join forces and consider expanding current and creating new theory and modeling programs--especially, 1. NASA should restore the HTMS program to its original support level to meet the critical needs of heliophysics science; 2. a Strategic Research Model program needs to be created to support model development for next-generation basic research codes; 3. new programs must be created for addressing mission-critical theory and modeling needs; and 4. enhanced programs are urgently required for training the next generation of theorists and modelers. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2209.03611v1-abstract-full').style.display = 'none'; document.getElementById('2209.03611v1-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 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">White paper submitted to Heliophysics 2024 Decadal Survey</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2208.04485">arXiv:2208.04485</a> <span> [<a href="https://arxiv.org/pdf/2208.04485">pdf</a>, <a href="https://arxiv.org/format/2208.04485">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/s11207-023-02170-1">10.1007/s11207-023-02170-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Defining the Middle Corona </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=West%2C+M+J">Matthew J. West</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=Wexler%2C+D+B">David B. Wexler</a>, <a href="/search/astro-ph?searchtype=author&query=Raymond%2C+J+C">John C. Raymond</a>, <a href="/search/astro-ph?searchtype=author&query=Del+Zanna%2C+G">Giulio Del Zanna</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=Kobelski%2C+A+R">Adam R. Kobelski</a>, <a href="/search/astro-ph?searchtype=author&query=DeForest%2C+C">Craig DeForest</a>, <a href="/search/astro-ph?searchtype=author&query=Golub%2C+L">Leon Golub</a>, <a href="/search/astro-ph?searchtype=author&query=Caspi%2C+A">Amir Caspi</a>, <a href="/search/astro-ph?searchtype=author&query=Gilly%2C+C+R">Chris R. Gilly</a>, <a href="/search/astro-ph?searchtype=author&query=Kooi%2C+J+E">Jason E. Kooi</a>, <a href="/search/astro-ph?searchtype=author&query=Alterman%2C+B+L">Benjamin L. Alterman</a>, <a href="/search/astro-ph?searchtype=author&query=Alzate%2C+N">Nathalia Alzate</a>, <a href="/search/astro-ph?searchtype=author&query=Banerjee%2C+D">Dipankar Banerjee</a>, <a href="/search/astro-ph?searchtype=author&query=Berghmans%2C+D">David Berghmans</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+B">Bin Chen</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=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Giordano%2C+S">Silvio Giordano</a>, <a href="/search/astro-ph?searchtype=author&query=Higginson%2C+A">Aleida Higginson</a>, <a href="/search/astro-ph?searchtype=author&query=Howard%2C+R+A">Russel A. Howard</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+E">Emily Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Mason%2C+J+P">James P. Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Meyer%2C+K+A">Karen A. Meyer</a> , et al. (9 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="2208.04485v2-abstract-short" style="display: inline;"> The middle corona, the region roughly spanning heliocentric altitudes from $1.5$ to $6\,R_\odot$, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. Eruptions that could disrupt the near-Earth environment propagate through it. Importantly, it modulates inflow from above that can drive dynamic changes at low… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.04485v2-abstract-full').style.display = 'inline'; document.getElementById('2208.04485v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2208.04485v2-abstract-full" style="display: none;"> The middle corona, the region roughly spanning heliocentric altitudes from $1.5$ to $6\,R_\odot$, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. Eruptions that could disrupt the near-Earth environment propagate through it. Importantly, it modulates inflow from above that can drive dynamic changes at lower heights in the inner corona. Consequently, this region is essential for comprehensively connecting the corona to the heliosphere and for developing corresponding global models. Nonetheless, because it is challenging to observe, the middle corona has been poorly studied by major solar remote sensing missions and instruments, extending back to the Solar and Heliospheric Observatory (SoHO) era. Thanks to recent advances in instrumentation, observational processing techniques, and a realization of the importance of the region, interest in the middle corona has increased. Although the region cannot be intrinsically separated from other regions of the solar atmosphere, there has emerged a need to define the region in terms of its location and extension in the solar atmosphere, its composition, the physical transitions it covers, and the underlying physics believed to be encapsulated by the region. This paper aims to define the middle corona and give an overview of the processes that occur there. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2208.04485v2-abstract-full').style.display = 'none'; document.getElementById('2208.04485v2-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 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">Working draft prepared by the middle corona heliophysics working group</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Solar Physics, Vol. 298, 78 (61pp); 2023 June 14 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2206.10106">arXiv:2206.10106</a> <span> [<a href="https://arxiv.org/pdf/2206.10106">pdf</a>, <a href="https://arxiv.org/format/2206.10106">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/ac8101">10.3847/1538-4357/ac8101 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Solar Minimum Eclipse of 2019 July 2: II. The First Absolute Brightness Measurements and MHD Model Predictions of Fe X, XI and XIV out to 3.4 Rs </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Boe%2C+B">Benjamin Boe</a>, <a href="/search/astro-ph?searchtype=author&query=Habbal%2C+S">Shadia Habbal</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Druckm%C3%BCller%2C+M">Miloslav Druckm眉ller</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="2206.10106v2-abstract-short" style="display: inline;"> We present the spatially resolved absolute brightness of the Fe X, Fe XI and Fe XIV visible coronal emission lines from 1.08 to 3.4 $R_\odot$, observed during the 2019 July 2 total solar eclipse (TSE). The morphology of the corona was typical of solar minimum, with a dipole field dominance showcased by large polar coronal holes and a broad equatorial streamer belt. The Fe XI line is found to be th… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.10106v2-abstract-full').style.display = 'inline'; document.getElementById('2206.10106v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2206.10106v2-abstract-full" style="display: none;"> We present the spatially resolved absolute brightness of the Fe X, Fe XI and Fe XIV visible coronal emission lines from 1.08 to 3.4 $R_\odot$, observed during the 2019 July 2 total solar eclipse (TSE). The morphology of the corona was typical of solar minimum, with a dipole field dominance showcased by large polar coronal holes and a broad equatorial streamer belt. The Fe XI line is found to be the brightest, followed by Fe X and Fe XIV (in disk $B_\odot$ units). All lines had brightness variations between streamers and coronal holes, where Fe XIV exhibited the largest variation. However, Fe X remained surprisingly uniform with latitude. The Fe line brightnesses are used to infer the relative ionic abundances and line of sight averaged electron temperature ($T_e$) throughout the corona, yielding values from 1.25 - 1.4 MK in coronal holes up to 1.65 MK in the core of streamers. The line brightnesses and inferred $T_e$ values are then quantitatively compared to the PSI Magnetohydrodynamic model prediction for this TSE. The MHD model predicted the Fe lines rather well in general, while the forward modeled line ratios slightly underestimated the observationally inferred $T_e$ within 5 to 10 % averaged over the entire corona. Larger discrepancies in the polar coronal holes may point to insufficient heating and/or other limitations in the approach. These comparisons highlight the importance of TSE observations for constraining models of the corona and solar wind formation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2206.10106v2-abstract-full').style.display = 'none'; document.getElementById('2206.10106v2-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 July, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 June, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">19 pages, 10 figures, accepted for publication 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/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/2205.03982">arXiv:2205.03982</a> <span> [<a href="https://arxiv.org/pdf/2205.03982">pdf</a>, <a href="https://arxiv.org/format/2205.03982">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/ac874e">10.3847/1538-4357/ac874e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Magnetogram-matching Method for Energizing Magnetic Flux Ropes Toward Eruption </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">Viacheslav S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</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="2205.03982v3-abstract-short" style="display: inline;"> We propose a new ``helicity-pumping'' method for energizing coronal equilibria that contain a magnetic flux rope (MFR) toward an eruption. We achieve this in a sequence of magnetohydrodynamics relaxations of small line-tied pulses of magnetic helicity, each of which is simulated by a suitable rescaling of the current-carrying part of the field. The whole procedure is ``magnetogram-matching'' becau… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.03982v3-abstract-full').style.display = 'inline'; document.getElementById('2205.03982v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.03982v3-abstract-full" style="display: none;"> We propose a new ``helicity-pumping'' method for energizing coronal equilibria that contain a magnetic flux rope (MFR) toward an eruption. We achieve this in a sequence of magnetohydrodynamics relaxations of small line-tied pulses of magnetic helicity, each of which is simulated by a suitable rescaling of the current-carrying part of the field. The whole procedure is ``magnetogram-matching'' because it involves no changes to the normal component of the field at the photospheric boundary. The method is illustrated by applying it to an observed force-free configuration whose MFR is modeled with our regularized Biot--Savart law method. We find that, in spite of the bipolar character of the external field, the MFR eruption is sustained by two reconnection processes. The first, which we refer to as breakthrough reconnection, is analogous to breakout reconnection in quadrupolar configurations. It occurs at a quasi-separator inside a current layer that wraps around the erupting MFR and is caused by the photospheric line-tying effect. The second process is the classical flare reconnection, which develops at the second quasi-separator inside a vertical current layer that is formed below the erupting MFR. Both reconnection processes work in tandem with the magnetic forces of the unstable MFR to propel it through the overlying ambient field, and their interplay may also be relevant for the thermal processes occurring in the plasma of solar flares. The considered example suggests that our method will be beneficial for both the modeling of observed eruptive events and theoretical studies of eruptions in idealized magnetic configurations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.03982v3-abstract-full').style.display = 'none'; document.getElementById('2205.03982v3-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 August, 2022; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 8 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">9 pages, 3 figures, new comments and references added, relative magnetic helicity calculated, fig. 2 modified, typos corrected, accepted to 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/2106.13344">arXiv:2106.13344</a> <span> [<a href="https://arxiv.org/pdf/2106.13344">pdf</a>, <a href="https://arxiv.org/format/2106.13344">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/10.1051/0004-6361/202140980">10.1051/0004-6361/202140980 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First light observations of the solar wind in the outer corona with the Metis coronagraph </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Romoli%2C+M">M. Romoli</a>, <a href="/search/astro-ph?searchtype=author&query=Antonucci%2C+E">E. Antonucci</a>, <a href="/search/astro-ph?searchtype=author&query=Andretta%2C+V">V. Andretta</a>, <a href="/search/astro-ph?searchtype=author&query=Capuano%2C+G+E">G. E. Capuano</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=De+Leo%2C+Y">Y. De Leo</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Fineschi%2C+S">S. Fineschi</a>, <a href="/search/astro-ph?searchtype=author&query=Heinzel%2C+P">P. Heinzel</a>, <a href="/search/astro-ph?searchtype=author&query=Landini%2C+F">F. Landini</a>, <a href="/search/astro-ph?searchtype=author&query=Liberatore%2C+A">A. Liberatore</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=Sasso%2C+C">C. Sasso</a>, <a href="/search/astro-ph?searchtype=author&query=Spadaro%2C+D">D. Spadaro</a>, <a href="/search/astro-ph?searchtype=author&query=Susino%2C+R">R. Susino</a>, <a href="/search/astro-ph?searchtype=author&query=Telloni%2C+D">D. Telloni</a>, <a href="/search/astro-ph?searchtype=author&query=Teriaca%2C+L">L. Teriaca</a>, <a href="/search/astro-ph?searchtype=author&query=Uslenghi%2C+M">M. Uslenghi</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+Y+M">Y. M. Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Bemporad%2C+A">A. Bemporad</a>, <a href="/search/astro-ph?searchtype=author&query=Capobianco%2C+G">G. Capobianco</a>, <a href="/search/astro-ph?searchtype=author&query=Casti%2C+M">M. Casti</a>, <a href="/search/astro-ph?searchtype=author&query=Fabi%2C+M">M. Fabi</a> , et al. (43 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="2106.13344v1-abstract-short" style="display: inline;"> The investigation of the wind in the solar corona initiated with the observations of the resonantly scattered UV emission of the coronal plasma obtained with UVCS-SOHO, designed to measure the wind outflow speed by applying the Doppler dimming diagnostics. Metis on Solar Orbiter complements the UVCS spectroscopic observations, performed during solar activity cycle 23, by simultaneously imaging the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.13344v1-abstract-full').style.display = 'inline'; document.getElementById('2106.13344v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.13344v1-abstract-full" style="display: none;"> The investigation of the wind in the solar corona initiated with the observations of the resonantly scattered UV emission of the coronal plasma obtained with UVCS-SOHO, designed to measure the wind outflow speed by applying the Doppler dimming diagnostics. Metis on Solar Orbiter complements the UVCS spectroscopic observations, performed during solar activity cycle 23, by simultaneously imaging the polarized visible light and the HI Ly-alpha corona in order to obtain high-spatial and temporal resolution maps of the outward velocity of the continuously expanding solar atmosphere. The Metis observations, on May 15, 2020, provide the first HI Ly-alpha images of the extended corona and the first instantaneous map of the speed of the coronal plasma outflows during the minimum of solar activity and allow us to identify the layer where the slow wind flow is observed. The polarized visible light (580-640 nm), and the UV HI Ly-alpha (121.6 nm) coronal emissions, obtained with the two Metis channels, are combined in order to measure the dimming of the UV emission relative to a static corona. This effect is caused by the outward motion of the coronal plasma along the direction of incidence of the chromospheric photons on the coronal neutral hydrogen. The plasma outflow velocity is then derived as a function of the measured Doppler dimming. The static corona UV emission is simulated on the basis of the plasma electron density inferred from the polarized visible light. This study leads to the identification, in the velocity maps of the solar corona, of the high-density layer about +/-10 deg wide, centered on the extension of a quiet equatorial streamer present at the East limb where the slowest wind flows at about (160 +/- 18) km/s from 4 Rs to 6 Rs. Beyond the boundaries of the high-density layer, the wind velocity rapidly increases, marking the transition between slow and fast wind in the corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.13344v1-abstract-full').style.display = 'none'; document.getElementById('2106.13344v1-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 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">Journal ref:</span> A&A, 2021, Forthcoming article </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2106.02789">arXiv:2106.02789</a> <span> [<a href="https://arxiv.org/pdf/2106.02789">pdf</a>, <a href="https://arxiv.org/format/2106.02789">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="Classical Physics">physics.class-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Fluid Dynamics">physics.flu-dyn</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/abfe0f">10.3847/1538-4365/abfe0f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Optimization of Magnetic Flux Ropes Modeled with the RBSL method </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">V. S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">T. T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">J. A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">R. M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">R. Lionello</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="2106.02789v1-abstract-short" style="display: inline;"> The so-called regularized Biot-Savart laws (RBSLs) provide an efficient and flexible method for modeling pre-eruptive magnetic configurations of coronal mass ejections (CMEs) whose characteristics are constrained by observational images and magnetic-field data. This method allows one to calculate the field of magnetic flux ropes (MFRs) with small circular cross-sections and an arbitrary axis shape… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.02789v1-abstract-full').style.display = 'inline'; document.getElementById('2106.02789v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2106.02789v1-abstract-full" style="display: none;"> The so-called regularized Biot-Savart laws (RBSLs) provide an efficient and flexible method for modeling pre-eruptive magnetic configurations of coronal mass ejections (CMEs) whose characteristics are constrained by observational images and magnetic-field data. This method allows one to calculate the field of magnetic flux ropes (MFRs) with small circular cross-sections and an arbitrary axis shape. The field of the whole configuration is constructed as a superposition of (1) such a flux-rope field and (2) an ambient potential field derived, for example, from an observed magnetogram. The RBSL kernels are determined from the requirement that the MFR field for a straight cylinder must be exactly force-free. For a curved MFR, however, the magnetic forces are generally unbalanced over the whole path of the MFR. To minimize these forces, we apply a modified Gauss-Newton method to find optimal MFR parameters. This is done by iteratively adjusting the MFR axis path and axial current. We then try to relax the resulting optimized configuration in a subsequent line-tied zero-beta magnetohydrodynamic simulation toward a force-free equilibrium. By considering two models of the sigmoidal pre-eruption configuration for the 2009 February 13 CME, we demonstrate how this approach works and what it is capable of. We show, in particular, that the building blocks of the core magnetic structure described by these models match to morphological features typically observed in such type of configurations. Our method will be useful for both the modeling of particular eruptive events and theoretical studies of idealized pre-eruptive MFR configurations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2106.02789v1-abstract-full').style.display = 'none'; document.getElementById('2106.02789v1-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 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">21 pages, 11 figures, accepted to ApJS</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2105.03772">arXiv:2105.03772</a> <span> [<a href="https://arxiv.org/pdf/2105.03772">pdf</a>, <a href="https://arxiv.org/format/2105.03772">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</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/10.3847/1538-4357/ac2dfc">10.3847/1538-4357/ac2dfc <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Comparative study of electric currents and energetic particle fluxes in a solar flare and Earth magnetospheric substorm </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Artemyev%2C+A">Anton Artemyev</a>, <a href="/search/astro-ph?searchtype=author&query=Zimovets%2C+I">Ivan Zimovets</a>, <a href="/search/astro-ph?searchtype=author&query=Sharykin%2C+I">Ivan Sharykin</a>, <a href="/search/astro-ph?searchtype=author&query=Nishimura%2C+Y">Yukitoshi Nishimura</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Weygand%2C+J">James Weygand</a>, <a href="/search/astro-ph?searchtype=author&query=Fiori%2C+R">Robyn Fiori</a>, <a href="/search/astro-ph?searchtype=author&query=Zhang%2C+X">Xiao-Jia Zhang</a>, <a href="/search/astro-ph?searchtype=author&query=Runov%2C+A">Andrei Runov</a>, <a href="/search/astro-ph?searchtype=author&query=Velli%2C+M">Marco Velli</a>, <a href="/search/astro-ph?searchtype=author&query=Angelopoulos%2C+V">Vassilis Angelopoulos</a>, <a href="/search/astro-ph?searchtype=author&query=Panasenco%2C+O">Olga Panasenco</a>, <a href="/search/astro-ph?searchtype=author&query=Russell%2C+C">Christopher Russell</a>, <a href="/search/astro-ph?searchtype=author&query=Miyoshi%2C+Y">Yoshizumi Miyoshi</a>, <a href="/search/astro-ph?searchtype=author&query=Kasahara%2C+S">Satoshi Kasahara</a>, <a href="/search/astro-ph?searchtype=author&query=Matsuoka%2C+A">Ayako Matsuoka</a>, <a href="/search/astro-ph?searchtype=author&query=Yokota%2C+S">Shoichiro Yokota</a>, <a href="/search/astro-ph?searchtype=author&query=Keika%2C+K">Kunihiro Keika</a>, <a href="/search/astro-ph?searchtype=author&query=Hori%2C+T">Tomoaki Hori</a>, <a href="/search/astro-ph?searchtype=author&query=Kazama%2C+Y">Yoichi Kazama</a>, <a href="/search/astro-ph?searchtype=author&query=Wang%2C+S">Shiang-Yu Wang</a>, <a href="/search/astro-ph?searchtype=author&query=Shinohara%2C+I">Iku Shinohara</a>, <a href="/search/astro-ph?searchtype=author&query=Ogawa%2C+Y">Yasunobu Ogawa</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="2105.03772v1-abstract-short" style="display: inline;"> Magnetic field-line reconnection is a universal plasma process responsible for the conversion of magnetic field energy to the plasma heating and charged particle acceleration. Solar flares and Earth's magnetospheric substorms are two most investigated dynamical systems where magnetic reconnection is believed to be responsible for global magnetic field reconfiguration and energization of plasma pop… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.03772v1-abstract-full').style.display = 'inline'; document.getElementById('2105.03772v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2105.03772v1-abstract-full" style="display: none;"> Magnetic field-line reconnection is a universal plasma process responsible for the conversion of magnetic field energy to the plasma heating and charged particle acceleration. Solar flares and Earth's magnetospheric substorms are two most investigated dynamical systems where magnetic reconnection is believed to be responsible for global magnetic field reconfiguration and energization of plasma populations. Such a reconfiguration includes formation of a long-living current systems connecting the primary energy release region and cold dense conductive plasma of photosphere/ionosphere. In both flares and substorms the evolution of this current system correlates with formation and dynamics of energetic particle fluxes. Our study is focused on this similarity between flares and substorms. Using a wide range of datasets available for flare and substorm investigations, we compare qualitatively dynamics of currents and energetic particle fluxes for one flare and one substorm. We showed that there is a clear correlation between energetic particle bursts (associated with energy release due to magnetic reconnection) and magnetic field reconfiguration/formation of current system. We then discuss how datasets of in-situ measurements in the magnetospheric substorm can help in interpretation of datasets gathered for the solar flare. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2105.03772v1-abstract-full').style.display = 'none'; document.getElementById('2105.03772v1-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 May, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.05837">arXiv:2103.05837</a> <span> [<a href="https://arxiv.org/pdf/2103.05837">pdf</a>, <a href="https://arxiv.org/format/2103.05837">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/ac090a">10.3847/1538-4357/ac090a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coronal Hole Detection and Open Magnetic Flux </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">J. A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Heinemann%2C+S+G">S. G. Heinemann</a>, <a href="/search/astro-ph?searchtype=author&query=Temmer%2C+M">M. Temmer</a>, <a href="/search/astro-ph?searchtype=author&query=Owens%2C+M+J">M. J. Owens</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">R. M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Arge%2C+C+N">C. N. Arge</a>, <a href="/search/astro-ph?searchtype=author&query=Asvestari%2C+E">E. Asvestari</a>, <a href="/search/astro-ph?searchtype=author&query=Delouille%2C+V">V. Delouille</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Hofmeister%2C+S+J">S. J. Hofmeister</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=Madjarska%2C+M">M. Madjarska</a>, <a href="/search/astro-ph?searchtype=author&query=Pinto%2C+R">R. Pinto</a>, <a href="/search/astro-ph?searchtype=author&query=Pomoell%2C+J">J. Pomoell</a>, <a href="/search/astro-ph?searchtype=author&query=Samara%2C+E">E. Samara</a>, <a href="/search/astro-ph?searchtype=author&query=Scolini%2C+C">C. Scolini</a>, <a href="/search/astro-ph?searchtype=author&query=Vrsnak%2C+B">B. Vrsnak</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="2103.05837v1-abstract-short" style="display: inline;"> Many scientists use coronal hole (CH) detections to infer open magnetic flux. Detection techniques differ in the areas that they assign as open, and may obtain different values for the open magnetic flux. We characterize the uncertainties of these methods, by applying six different detection methods to deduce the area and open flux of a near-disk center CH observed on 9/19/2010, and applying a sin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.05837v1-abstract-full').style.display = 'inline'; document.getElementById('2103.05837v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.05837v1-abstract-full" style="display: none;"> Many scientists use coronal hole (CH) detections to infer open magnetic flux. Detection techniques differ in the areas that they assign as open, and may obtain different values for the open magnetic flux. We characterize the uncertainties of these methods, by applying six different detection methods to deduce the area and open flux of a near-disk center CH observed on 9/19/2010, and applying a single method to five different EUV filtergrams for this CH. Open flux was calculated using five different magnetic maps. The standard deviation (interpreted as the uncertainty) in the open flux estimate for this CH was about 26%. However, including the variability of different magnetic data sources, this uncertainty almost doubles to 45%. We use two of the methods to characterize the area and open flux for all CHs in this time period. We find that the open flux is greatly underestimated compared to values inferred from in-situ measurements (by 2.2-4 times). We also test our detection techniques on simulated emission images from a thermodynamic MHD model of the solar corona. We find that the methods overestimate the area and open flux in the simulated CH, but the average error in the flux is only about 7%. The full-Sun detections on the simulated corona underestimate the model open flux, but by factors well below what is needed to account for the missing flux in the observations. Under-detection of open flux in coronal holes likely contributes to the recognized deficit in solar open flux, but is unlikely to resolve it. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.05837v1-abstract-full').style.display = 'none'; document.getElementById('2103.05837v1-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 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">28 pages, 10 figures, submitted to 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/2103.02113">arXiv:2103.02113</a> <span> [<a href="https://arxiv.org/pdf/2103.02113">pdf</a>, <a href="https://arxiv.org/format/2103.02113">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/abea79">10.3847/1538-4357/abea79 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Color and Brightness of the F-Corona Inferred from the 2019 July 2 Total Solar Eclipse </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Boe%2C+B">Benjamin Boe</a>, <a href="/search/astro-ph?searchtype=author&query=Habbal%2C+S">Shadia Habbal</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Druckmuller%2C+M">Miloslav Druckmuller</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="2103.02113v1-abstract-short" style="display: inline;"> Total solar eclipses (TSEs) provide a unique opportunity to quantify the properties of the K-corona (electrons), F-corona (dust) and E-corona (ions) continuously from the solar surface out to a few solar radii. We apply a novel inversion method to separate emission from the K- and F-corona continua using unpolarized total brightness (tB) observations from five 0.5 nm bandpasses acquired during the… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.02113v1-abstract-full').style.display = 'inline'; document.getElementById('2103.02113v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.02113v1-abstract-full" style="display: none;"> Total solar eclipses (TSEs) provide a unique opportunity to quantify the properties of the K-corona (electrons), F-corona (dust) and E-corona (ions) continuously from the solar surface out to a few solar radii. We apply a novel inversion method to separate emission from the K- and F-corona continua using unpolarized total brightness (tB) observations from five 0.5 nm bandpasses acquired during the 2019 July 2 TSE between 529.5 nm and 788.4 nm. The wavelength dependence relative to the photosphere (i.e., color) of the F-corona itself is used to infer the tB of the K- and F-corona for each line-of-sight. We compare our K-corona emission results with the Mauna Loa Solar Observatory (MLSO) K-Cor polarized brightness (pB) observations from the day of the eclipse, and the forward modeled K-corona intensity from the Predictive Science Inc. (PSI) Magnetohydrodynamic (MHD) model prediction. Our results are generally consistent with previous work and match both the MLSO data and PSI-MHD predictions quite well, supporting the validity of our approach and of the PSI-MHD model. However, we find that the tB of the F-corona is higher than expected in the low corona, perhaps indicating that the F-corona is slightly polarized -- challenging the common assumption that the F-corona is entirely unpolarized. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.02113v1-abstract-full').style.display = 'none'; document.getElementById('2103.02113v1-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> 2 March, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">25 pages, 9 figures, accepted for publication 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/2102.05618">arXiv:2102.05618</a> <span> [<a href="https://arxiv.org/pdf/2102.05618">pdf</a>, <a href="https://arxiv.org/format/2102.05618">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/abfd2f">10.3847/1538-4357/abfd2f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Variations in Finite Difference Potential Fields </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Mikic%2C+Z">Zoran Mikic</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="2102.05618v1-abstract-short" style="display: inline;"> The potential field (PF) solution of the solar corona is a vital modeling tool for a wide range of applications, including minimum energy estimates, coronal magnetic field modeling, and empirical solar wind solutions. Given its popularity, it is important to understand how choices made in computing a PF may influence key properties of the solution. Here we study PF solutions for the global coronal… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05618v1-abstract-full').style.display = 'inline'; document.getElementById('2102.05618v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.05618v1-abstract-full" style="display: none;"> The potential field (PF) solution of the solar corona is a vital modeling tool for a wide range of applications, including minimum energy estimates, coronal magnetic field modeling, and empirical solar wind solutions. Given its popularity, it is important to understand how choices made in computing a PF may influence key properties of the solution. Here we study PF solutions for the global coronal magnetic field on 2012 June 13, computed with our high-performance finite difference code POT3D. Solutions are analyzed for their global properties and locally around NOAA AR 11504, using the net open flux, open field boundaries, total magnetic energy, and magnetic structure as metrics. We explore how PF solutions depend on 1) the data source, type, and processing of the inner boundary conditions, 2) the choice of the outer boundary condition height and type, and 3) the numerical resolution and spatial scale of information at the lower boundary. We discuss the various qualitative and quantitative differences that naturally arise by using different maps as input, and illustrate how coronal morphology and open flux depend most strongly on the outer boundary condition. We also show how large-scale morphologies and the open magnetic flux are remarkably insensitive to model resolution, while the surface mapping and embedded magnetic complexity vary considerably. This establishes important context for past, current, and future applications of the PF for coronal and solar wind modeling. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05618v1-abstract-full').style.display = 'none'; document.getElementById('2102.05618v1-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">27 pages, 18 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/2102.05101">arXiv:2102.05101</a> <span> [<a href="https://arxiv.org/pdf/2102.05101">pdf</a>, <a href="https://arxiv.org/format/2102.05101">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</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/10.1051/0004-6361/202039815">10.1051/0004-6361/202039815 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Using Parker Solar Probe observations during the first four perihelia to constrain global magnetohydrodynamic models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">Pete Riley</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Badman%2C+S+T">Samuel T. Badman</a>, <a href="/search/astro-ph?searchtype=author&query=Stevens%2C+M+L">Michael L. Stevens</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="2102.05101v1-abstract-short" style="display: inline;"> Parker Solar Probe (PSP) is providing an unprecedented view of the Sun's corona as it progressively dips closer into the solar atmosphere with each solar encounter. Each set of observations provides a unique opportunity to test and constrain global models of the solar corona and inner heliosphere and, in turn, use the model results to provide a global context for interpreting such observations. In… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05101v1-abstract-full').style.display = 'inline'; document.getElementById('2102.05101v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2102.05101v1-abstract-full" style="display: none;"> Parker Solar Probe (PSP) is providing an unprecedented view of the Sun's corona as it progressively dips closer into the solar atmosphere with each solar encounter. Each set of observations provides a unique opportunity to test and constrain global models of the solar corona and inner heliosphere and, in turn, use the model results to provide a global context for interpreting such observations. In this study, we develop a set of global magnetohydrodynamic (MHD) model solutions of varying degrees of sophistication for PSP's first four encounters and compare the results with in situ measurements from PSP, Stereo-A, and Earth-based spacecraft, with the objective of assessing which models perform better or worse. All models were primarily driven by the observed photospheric magnetic field using data from Solar Dynamics Observatory's Helioseismic and Magnetic Imager (HMI) instrument. Overall, we find that there are substantial differences between the model results, both in terms of the large-scale structure of the inner heliosphere during these time periods, as well as in the inferred time-series at various spacecraft. The "thermodynamic" model, which represents the "middle ground", in terms of model complexity, appears to reproduce the observations most closely for all four encounters. Our results also contradict an earlier study that had hinted that the open flux problem may disappear nearer the Sun. Instead, our results suggest that this "missing" solar flux is still missing even at 26.9 Rs, and thus it cannot be explained by interplanetary processes. Finally, the model results were also used to provide a global context for interpreting the localized in situ measurements. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2102.05101v1-abstract-full').style.display = 'none'; document.getElementById('2102.05101v1-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> 9 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 650, A19 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2012.09078">arXiv:2012.09078</a> <span> [<a href="https://arxiv.org/pdf/2012.09078">pdf</a>, <a href="https://arxiv.org/format/2012.09078">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/abdf5f">10.3847/1538-4357/abdf5f <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Energetic Proton Propagation and Acceleration Simulated for the Bastille Day Event of July 14, 2000 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Young%2C+M+A">Matthew A. Young</a>, <a href="/search/astro-ph?searchtype=author&query=Schwadron%2C+N+A">Nathan A. Schwadron</a>, <a href="/search/astro-ph?searchtype=author&query=Gorby%2C+M">Matthew Gorby</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J">Jon Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">Pete Riley</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V">Viacheslav Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Mewaldt%2C+R+A">Richard A. Mewaldt</a>, <a href="/search/astro-ph?searchtype=author&query=Cohen%2C+C+M+S">Christina M. S. Cohen</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="2012.09078v2-abstract-short" style="display: inline;"> This work presents results from simulations of the 14 July 2000 ("Bastille Day") solar proton event. We used the Energetic Particle Radiation Environment Model (EPREM) and the CORona-HELiosphere (CORHEL) software suite within the SPE Threat Assessment Tool (STAT) framework to model proton acceleration to GeV energies due to the passage of a CME through the low solar corona, and compared the model… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.09078v2-abstract-full').style.display = 'inline'; document.getElementById('2012.09078v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2012.09078v2-abstract-full" style="display: none;"> This work presents results from simulations of the 14 July 2000 ("Bastille Day") solar proton event. We used the Energetic Particle Radiation Environment Model (EPREM) and the CORona-HELiosphere (CORHEL) software suite within the SPE Threat Assessment Tool (STAT) framework to model proton acceleration to GeV energies due to the passage of a CME through the low solar corona, and compared the model results to GOES-08 observations. The coupled simulation models particle acceleration from 1 to 20 $R_\odot$, after which it models only particle transport. The simulation roughly reproduces the peak event fluxes, and timing and spatial location of the energetic particle event. While peak fluxes and overall variation within the first few hours of the simulation agree well with observations, the modeled CME moves beyond the inner simulation boundary after several hours. The model therefore accurately describes the acceleration processes in the low corona and resolves the sites of most rapid acceleration close to the Sun. Plots of integral flux envelopes from multiple simulated observers near Earth further improve the comparison to observations and increase potential for predicting solar particle events. Broken-power-law fits to fluence spectra agree with diffusive acceleration theory over the low energy range. Over the high energy range, they demonstrate the variability in acceleration rate and mirror the inter-event variability observed solar-cycle 23 GLEs. We discuss ways to improve STAT predictions, including using corrected GOES energy bins and computing fits to the seed spectrum. This paper demonstrates a predictive tool for simulating low-coronal SEP acceleration. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2012.09078v2-abstract-full').style.display = 'none'; document.getElementById('2012.09078v2-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 January, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 December, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">18 pages; 9 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/1905.05299">arXiv:1905.05299</a> <span> [<a href="https://arxiv.org/pdf/1905.05299">pdf</a>, <a href="https://arxiv.org/format/1905.05299">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/10.1088/1742-6596/1225/1/012007">10.1088/1742-6596/1225/1/012007 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Coupled MHD-Focused Transport Simulations for Modeling Solar Particle Events </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Schwadron%2C+N">Nathan Schwadron</a>, <a href="/search/astro-ph?searchtype=author&query=Gorby%2C+M">Matthew Gorby</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Torok%2C+T">Tibor Torok</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Wijaya%2C+J">Janvier Wijaya</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="1905.05299v1-abstract-short" style="display: inline;"> We describe the initial version of the Solar Particle Event (SPE) Threat Assessment Tool or STAT. STAT relies on elements of Corona-Heliosphere (CORHEL) and the Earth-Moon-Mars Radiation Environment Module (EMMREM), and allows users to investigate coronal mass ejection (CME) driven SPEs using coupled magnetohydrodynamic (MHD) and focused transport solutions. At the present time STAT focuses on mod… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.05299v1-abstract-full').style.display = 'inline'; document.getElementById('1905.05299v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.05299v1-abstract-full" style="display: none;"> We describe the initial version of the Solar Particle Event (SPE) Threat Assessment Tool or STAT. STAT relies on elements of Corona-Heliosphere (CORHEL) and the Earth-Moon-Mars Radiation Environment Module (EMMREM), and allows users to investigate coronal mass ejection (CME) driven SPEs using coupled magnetohydrodynamic (MHD) and focused transport solutions. At the present time STAT focuses on modeling solar energetic particle (SEP) acceleration in and transport from the low corona, where the highest energy SEP events are generated. We illustrate STAT's capabilities with a model of the July 14, 2000 "Bastille Day" event, including innovative diagnostics for understanding the three-dimensional distribution of particle fluxes and their relation to the structure of the underlying CME driver. A preliminary comparison with NOAA GOES measurements is shown. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.05299v1-abstract-full').style.display = 'none'; document.getElementById('1905.05299v1-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 May, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">13 pages, 6 figures, accepted for publication in Journal of Physics Conf. Ser. ASTRONUM 2018</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1902.09673">arXiv:1902.09673</a> <span> [<a href="https://arxiv.org/pdf/1902.09673">pdf</a>, <a href="https://arxiv.org/format/1902.09673">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Space Physics">physics.space-ph</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/10.3847/2041-8213/ab0ec3">10.3847/2041-8213/ab0ec3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Predicting the Structure of the Solar Corona and Inner Heliosphere during Parker Solar Probe's First Perihelion Pass </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">Pete Riley</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Mikic%2C+Z">Zoran Mikic</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</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="1902.09673v2-abstract-short" style="display: inline;"> NASA's Parker Solar Probe (Parker) spacecraft reached its first perihelion of 35.7 solar radii on November 5th, 2018. To aid in mission planning, and in anticipation of the unprecedented measurements to be returned, in late October, we developed a three-dimensional magnetohydrodynamic (MHD) solution for the solar corona and inner heliosphere, driven by the then available observations of the Sun's… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.09673v2-abstract-full').style.display = 'inline'; document.getElementById('1902.09673v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1902.09673v2-abstract-full" style="display: none;"> NASA's Parker Solar Probe (Parker) spacecraft reached its first perihelion of 35.7 solar radii on November 5th, 2018. To aid in mission planning, and in anticipation of the unprecedented measurements to be returned, in late October, we developed a three-dimensional magnetohydrodynamic (MHD) solution for the solar corona and inner heliosphere, driven by the then available observations of the Sun's photospheric magnetic field. Our model incorporates a wave-turbulence-driven (WTD) model to heat the corona. Here, we present our predictions for the structure of the solar corona and the likely {\it in situ} measurements that Parker will be returning over the next few months. We infer that, in the days prior to 1st Encounter, Parker was immersed in wind emanating from a positive-polarity equatorial coronal hole. During the encounter, however, field lines from the spacecraft mapped to another, negative-polarity equatorial coronal hole. Following the encounter, Parker was magnetically connected to the large, positive-polarity northern polar coronal hole. When the Parker data become available, these model results can be used to assist in their calibration and interpretation, and, additionally, provide a global context for interpreting the localized {\it in situ} measurements. In particular, we can identify what types of solar wind Parker encountered, what the underlying magnetic structure was, and how complexities in the orbital trajectory can be interpreted within a global, inertial frame. Ultimately, the measurements returned by Parker can be used to constrain current theories for heating the solar corona and accelerating the solar wind. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1902.09673v2-abstract-full').style.display = 'none'; document.getElementById('1902.09673v2-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 June, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 February, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2019. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1901.03748">arXiv:1901.03748</a> <span> [<a href="https://arxiv.org/pdf/1901.03748">pdf</a>, <a href="https://arxiv.org/ps/1901.03748">ps</a>, <a href="https://arxiv.org/format/1901.03748">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/s11207-019-1401-2">10.1007/s11207-019-1401-2 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ion Charge States in a Time-Dependent Wave-Turbulence-Driven Model of the Solar Wind </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Zoran Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=Raymond%2C+J">John Raymond</a>, <a href="/search/astro-ph?searchtype=author&query=Shen%2C+C">Chengcai Shen</a>, <a href="/search/astro-ph?searchtype=author&query=Velli%2C+M">Marco Velli</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="1901.03748v1-abstract-short" style="display: inline;"> Ion fractional charge states, measured in situ in the heliosphere, depend on the properties of the plasma in the inner corona. As the ions travel outward in the solar wind and the electron density drops, the charge states remain essentially unaltered or "frozen in". Thus they can provide a powerful constraint on heating models of the corona and acceleration of the solar wind. We have implemented n… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.03748v1-abstract-full').style.display = 'inline'; document.getElementById('1901.03748v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1901.03748v1-abstract-full" style="display: none;"> Ion fractional charge states, measured in situ in the heliosphere, depend on the properties of the plasma in the inner corona. As the ions travel outward in the solar wind and the electron density drops, the charge states remain essentially unaltered or "frozen in". Thus they can provide a powerful constraint on heating models of the corona and acceleration of the solar wind. We have implemented non-equilibrium ionization calculations into a 1D wave-turbulence-driven (WTD) hydrodynamic solar wind model and compared modeled charge states with the Ulysses 1994-5 in situ measurements. We have found that modeled charge state ratios of $C^{6+}/C^{5+}$ and $O^{7+}/O^{6+}$, among others, were too low compared with Ulysses measurements. However, a heuristic reduction of the plasma flow speed has been able to bring the modeled results in line with observations, though other ideas have been proposed to address this discrepancy. We discuss implications of our results and the prospect of including ion charge state calculations into our 3D MHD model of the inner heliosphere. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1901.03748v1-abstract-full').style.display = 'none'; document.getElementById('1901.03748v1-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> 11 January, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">To appear in Solar 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/1811.08329">arXiv:1811.08329</a> <span> [<a href="https://arxiv.org/pdf/1811.08329">pdf</a>, <a href="https://arxiv.org/format/1811.08329">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/ab21db">10.3847/1538-4357/ab21db <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Unfolding overlapped slitless imaging spectrometer data for extended sources </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Winebarger%2C+A">Amy Winebarger</a>, <a href="/search/astro-ph?searchtype=author&query=Weber%2C+M">Mark Weber</a>, <a href="/search/astro-ph?searchtype=author&query=Bethge%2C+C">Christian Bethge</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Golub%2C+L">Leon Golub</a>, <a href="/search/astro-ph?searchtype=author&query=DeLuca%2C+E">Edward DeLuca</a>, <a href="/search/astro-ph?searchtype=author&query=Savage%2C+S">Sabrina Savage</a>, <a href="/search/astro-ph?searchtype=author&query=Del+Zanna%2C+G">Giulio Del Zanna</a>, <a href="/search/astro-ph?searchtype=author&query=Samra%2C+J">Jenna Samra</a>, <a href="/search/astro-ph?searchtype=author&query=Madsen%2C+C">Chad Madsen</a>, <a href="/search/astro-ph?searchtype=author&query=Ashraf%2C+A">Afra Ashraf</a>, <a href="/search/astro-ph?searchtype=author&query=Carter%2C+C">Courtney Carter</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="1811.08329v2-abstract-short" style="display: inline;"> Slitless spectrometers can provide simultaneous imaging and spectral data over an extended field of view, thereby allowing rapid data acquisition for extended sources. In some instances, when the object is greatly extended or the spectral dispersion is too small, there may be locations in the focal plane where contributions from emission lines at different wavelengths contribute. It is then desira… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.08329v2-abstract-full').style.display = 'inline'; document.getElementById('1811.08329v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.08329v2-abstract-full" style="display: none;"> Slitless spectrometers can provide simultaneous imaging and spectral data over an extended field of view, thereby allowing rapid data acquisition for extended sources. In some instances, when the object is greatly extended or the spectral dispersion is too small, there may be locations in the focal plane where contributions from emission lines at different wavelengths contribute. It is then desirable to unfold the overlapped regions in order to isolate the contributions from the individual wavelengths. In this paper, we describe a method for such an unfolding, using an inversion technique developed for an extreme ultraviolet imaging spectrometer and coronagraph named the COronal Spectroscopic Imager in the EUV (COSIE). The COSIE spectrometer wavelength range (18.6 - 20.5 nm) contains a number of strong coronal emission lines and several density sensitive lines. We focus on optimizing the unfolding process to retrieve emission measure maps at constant temperature, maps of spectrally pure intensity in the Fe XII and Fe XIII lines and density maps based on both Fe XII and Fe XIII diagnostics. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.08329v2-abstract-full').style.display = 'none'; document.getElementById('1811.08329v2-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 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">22 pages</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1811.02605">arXiv:1811.02605</a> <span> [<a href="https://arxiv.org/pdf/1811.02605">pdf</a>, <a href="https://arxiv.org/format/1811.02605">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Computational Physics">physics.comp-ph</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="Distributed, Parallel, and Cluster Computing">cs.DC</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Programming Languages">cs.PL</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/10.1088/1742-6596/1225/1/012012">10.1088/1742-6596/1225/1/012012 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> GPU Acceleration of an Established Solar MHD Code using OpenACC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">R. M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">J. A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Z. Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">T. T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">V. S. Titov</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="1811.02605v1-abstract-short" style="display: inline;"> GPU accelerators have had a notable impact on high-performance computing across many disciplines. They provide high performance with low cost/power, and therefore have become a primary compute resource on many of the largest supercomputers. Here, we implement multi-GPU acceleration into our Solar MHD code (MAS) using OpenACC in a fully portable, single-source manner. Our preliminary implementation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02605v1-abstract-full').style.display = 'inline'; document.getElementById('1811.02605v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1811.02605v1-abstract-full" style="display: none;"> GPU accelerators have had a notable impact on high-performance computing across many disciplines. They provide high performance with low cost/power, and therefore have become a primary compute resource on many of the largest supercomputers. Here, we implement multi-GPU acceleration into our Solar MHD code (MAS) using OpenACC in a fully portable, single-source manner. Our preliminary implementation is focused on MAS running in a reduced physics "zero-beta" mode. While valuable on its own, our main goal is to pave the way for a full physics, thermodynamic MHD implementation. We describe the OpenACC implementation methodology and challenges. "Time-to-solution" performance results of a production-level flux rope eruption simulation on multi-CPU and multi-GPU systems are shown. We find that the GPU-accelerated MAS code has the ability to run "zero-beta" simulations on a single multi-GPU server at speeds previously requiring multiple CPU server-nodes of a supercomputer. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1811.02605v1-abstract-full').style.display = 'none'; document.getElementById('1811.02605v1-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> 6 November, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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, 9 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/1810.08728">arXiv:1810.08728</a> <span> [<a href="https://arxiv.org/pdf/1810.08728">pdf</a>, <a href="https://arxiv.org/ps/1810.08728">ps</a>, <a href="https://arxiv.org/format/1810.08728">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"> Roadmap for Reliable Ensemble Forecasting of the Sun-Earth System </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Nita%2C+G">Gelu Nita</a>, <a href="/search/astro-ph?searchtype=author&query=Angryk%2C+R">Rafal Angryk</a>, <a href="/search/astro-ph?searchtype=author&query=Aydin%2C+B">Berkay Aydin</a>, <a href="/search/astro-ph?searchtype=author&query=Banda%2C+J">Juan Banda</a>, <a href="/search/astro-ph?searchtype=author&query=Bastian%2C+T">Tim Bastian</a>, <a href="/search/astro-ph?searchtype=author&query=Berger%2C+T">Tom Berger</a>, <a href="/search/astro-ph?searchtype=author&query=Bindi%2C+V">Veronica Bindi</a>, <a href="/search/astro-ph?searchtype=author&query=Boucheron%2C+L">Laura Boucheron</a>, <a href="/search/astro-ph?searchtype=author&query=Cao%2C+W">Wenda Cao</a>, <a href="/search/astro-ph?searchtype=author&query=Christian%2C+E">Eric Christian</a>, <a href="/search/astro-ph?searchtype=author&query=de+Nolfo%2C+G">Georgia de Nolfo</a>, <a href="/search/astro-ph?searchtype=author&query=DeLuca%2C+E">Edward DeLuca</a>, <a href="/search/astro-ph?searchtype=author&query=DeRosa%2C+M">Marc DeRosa</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Fleishman%2C+G">Gregory Fleishman</a>, <a href="/search/astro-ph?searchtype=author&query=Fuentes%2C+O">Olac Fuentes</a>, <a href="/search/astro-ph?searchtype=author&query=Gary%2C+D">Dale Gary</a>, <a href="/search/astro-ph?searchtype=author&query=Hill%2C+F">Frank Hill</a>, <a href="/search/astro-ph?searchtype=author&query=Hoeksema%2C+T">Todd Hoeksema</a>, <a href="/search/astro-ph?searchtype=author&query=Hu%2C+Q">Qiang Hu</a>, <a href="/search/astro-ph?searchtype=author&query=Ilie%2C+R">Raluca Ilie</a>, <a href="/search/astro-ph?searchtype=author&query=Ireland%2C+J">Jack Ireland</a>, <a href="/search/astro-ph?searchtype=author&query=Kamalabadi%2C+F">Farzad Kamalabadi</a>, <a href="/search/astro-ph?searchtype=author&query=Korreck%2C+K">Kelly Korreck</a>, <a href="/search/astro-ph?searchtype=author&query=Kosovichev%2C+A">Alexander Kosovichev</a> , et al. (22 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="1810.08728v2-abstract-short" style="display: inline;"> The authors of this report met on 28-30 March 2018 at the New Jersey Institute of Technology, Newark, New Jersey, for a 3-day workshop that brought together a group of data providers, expert modelers, and computer and data scientists, in the solar discipline. Their objective was to identify challenges in the path towards building an effective framework to achieve transformative advances in the und… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.08728v2-abstract-full').style.display = 'inline'; document.getElementById('1810.08728v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1810.08728v2-abstract-full" style="display: none;"> The authors of this report met on 28-30 March 2018 at the New Jersey Institute of Technology, Newark, New Jersey, for a 3-day workshop that brought together a group of data providers, expert modelers, and computer and data scientists, in the solar discipline. Their objective was to identify challenges in the path towards building an effective framework to achieve transformative advances in the understanding and forecasting of the Sun-Earth system from the upper convection zone of the Sun to the Earth's magnetosphere. The workshop aimed to develop a research roadmap that targets the scientific challenge of coupling observations and modeling with emerging data-science research to extract knowledge from the large volumes of data (observed and simulated) while stimulating computer science with new research applications. The desire among the attendees was to promote future trans-disciplinary collaborations and identify areas of convergence across disciplines. The workshop combined a set of plenary sessions featuring invited introductory talks and workshop progress reports, interleaved with a set of breakout sessions focused on specific topics of interest. Each breakout group generated short documents, listing the challenges identified during their discussions in addition to possible ways of attacking them collectively. These documents were combined into this report-wherein a list of prioritized activities have been collated, shared and endorsed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1810.08728v2-abstract-full').style.display = 'none'; document.getElementById('1810.08728v2-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> 29 October, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 19 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">Comments:</span> <span class="has-text-grey-dark mathjax">Workshop Report</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1808.00785">arXiv:1808.00785</a> <span> [<a href="https://arxiv.org/pdf/1808.00785">pdf</a>, <a href="https://arxiv.org/ps/1808.00785">ps</a>, <a href="https://arxiv.org/format/1808.00785">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/s11214-018-0534-1">10.1007/s11214-018-0534-1 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Global Non-Potential Magnetic Models of the Solar Corona During the March 2015 Eclipse </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Yeates%2C+A+R">A. R. Yeates</a>, <a href="/search/astro-ph?searchtype=author&query=Amari%2C+T">T. Amari</a>, <a href="/search/astro-ph?searchtype=author&query=Contopoulos%2C+I">I. Contopoulos</a>, <a href="/search/astro-ph?searchtype=author&query=Feng%2C+X">X. Feng</a>, <a href="/search/astro-ph?searchtype=author&query=Mackay%2C+D+H">D. H. Mackay</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Z. Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=Wiegelmann%2C+T">T. Wiegelmann</a>, <a href="/search/astro-ph?searchtype=author&query=Hutton%2C+J">J. Hutton</a>, <a href="/search/astro-ph?searchtype=author&query=Lowder%2C+C+A">C. A. Lowder</a>, <a href="/search/astro-ph?searchtype=author&query=Morgan%2C+H">H. Morgan</a>, <a href="/search/astro-ph?searchtype=author&query=Petrie%2C+G">G. Petrie</a>, <a href="/search/astro-ph?searchtype=author&query=Rachmeler%2C+L+A">L. A. Rachmeler</a>, <a href="/search/astro-ph?searchtype=author&query=Upton%2C+L+A">L. A. Upton</a>, <a href="/search/astro-ph?searchtype=author&query=Canou%2C+A">A. Canou</a>, <a href="/search/astro-ph?searchtype=author&query=Chopin%2C+P">P. Chopin</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Druckm%C3%BCller%2C+M">M. Druckm眉ller</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">J. A. Linker</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=T%C3%B6r%C3%B6k%2C+T">T. T枚r枚k</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="1808.00785v1-abstract-short" style="display: inline;"> Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated electric currents are developed in significantly different ways. This is not a direct comparison of the coronal modelling techniques, in that the different models a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.00785v1-abstract-full').style.display = 'inline'; document.getElementById('1808.00785v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1808.00785v1-abstract-full" style="display: none;"> Seven different models are applied to the same problem of simulating the Sun's coronal magnetic field during the solar eclipse on 2015 March 20. All of the models are non-potential, allowing for free magnetic energy, but the associated electric currents are developed in significantly different ways. This is not a direct comparison of the coronal modelling techniques, in that the different models also use different photospheric boundary conditions, reflecting the range of approaches currently used in the community. Despite the significant differences, the results show broad agreement in the overall magnetic topology. Among those models with significant volume currents in much of the corona, there is general agreement that the ratio of total to potential magnetic energy should be approximately 1.4. However, there are significant differences in the electric current distributions; while static extrapolations are best able to reproduce active regions, they are unable to recover sheared magnetic fields in filament channels using currently available vector magnetogram data. By contrast, time-evolving simulations can recover the filament channel fields at the expense of not matching the observed vector magnetic fields within active regions. We suggest that, at present, the best approach may be a hybrid model using static extrapolations but with additional energization informed by simplified evolution models. This is demonstrated by one of the models. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1808.00785v1-abstract-full').style.display = 'none'; document.getElementById('1808.00785v1-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> 2 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">29 pages, 11 figures, accepted for publication in Space Science Reviews</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.09847">arXiv:1807.09847</a> <span> [<a href="https://arxiv.org/pdf/1807.09847">pdf</a>, <a href="https://arxiv.org/format/1807.09847">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> </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/aad77b">10.3847/2041-8213/aad77b <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A Truly Global Extreme Ultraviolet Wave from the SOL2017-09-10 X8.2+ Solar Flare-Coronal Mass Ejection </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Liu%2C+W">Wei Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Jin%2C+M">Meng Jin</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Ofman%2C+L">Leon Ofman</a>, <a href="/search/astro-ph?searchtype=author&query=Cheung%2C+M+C+M">Mark C. M. Cheung</a>, <a href="/search/astro-ph?searchtype=author&query=Nitta%2C+N+V">Nariaki V. Nitta</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="1807.09847v2-abstract-short" style="display: inline;"> We report SDO/AIA observations of an extraordinary global extreme ultraviolet (EUV) wave triggered by the X8.2+ flare-CME eruption on 2017 September 10. This was one of the best EUV waves ever observed with modern instruments, yet it was likely the last one of such magnitudes of Solar Cycle 24 as the Sun heads toward the minimum. Its remarkable characteristics include the following. (1) The wave w… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09847v2-abstract-full').style.display = 'inline'; document.getElementById('1807.09847v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.09847v2-abstract-full" style="display: none;"> We report SDO/AIA observations of an extraordinary global extreme ultraviolet (EUV) wave triggered by the X8.2+ flare-CME eruption on 2017 September 10. This was one of the best EUV waves ever observed with modern instruments, yet it was likely the last one of such magnitudes of Solar Cycle 24 as the Sun heads toward the minimum. Its remarkable characteristics include the following. (1) The wave was observed, for the first time, to traverse the full-Sun corona over the entire visible solar disk and off-limb circumference, manifesting a truly global nature, owing to its exceptionally large amplitude, e.g., with EUV enhancements by up to 300% at 1.1 Rsun from the eruption. (2) This leads to strong transmissions (in addition to commonly observed reflections) in and out of both polar coronal holes, which are usually devoid of EUV waves. It has elevated wave speeds >2000 km/s within them, consistent with the expected higher fast-mode magnetosonic wave speeds. The coronal holes essentially serve as new "radiation centers" for the waves being refracted out of them, which then travel toward the equator and collide head-on, causing additional EUV enhancements. (3) The wave produces significant compressional heating to local plasma upon its impact, indicated by long-lasting EUV intensity changes and differential emission measure increases at higher temperatures (e.g., log T=6.2) accompanied by decreases at lower temperatures (e.g., log T=6.0). These characteristics signify the potential of such EUV waves for novel magnetic and thermal diagnostics of the solar corona {\it on global scales}. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.09847v2-abstract-full').style.display = 'none'; document.getElementById('1807.09847v2-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 August, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 25 July, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">Accepted by ApJ Letters (as of July 24, 2018), 8 pages, 5 figures; Update: minor edits made on August 14, 2018, after submitting ApJL proof corrections</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1807.00020">arXiv:1807.00020</a> <span> [<a href="https://arxiv.org/pdf/1807.00020">pdf</a>, <a href="https://arxiv.org/format/1807.00020">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/aacce3">10.3847/1538-4357/aacce3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Sequential eruptions triggered by flux emergence - observations and modeling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Dacie%2C+S">Sally Dacie</a>, <a href="/search/astro-ph?searchtype=author&query=Torok%2C+T">Tibor Torok</a>, <a href="/search/astro-ph?searchtype=author&query=Demoulin%2C+P">Pascal Demoulin</a>, <a href="/search/astro-ph?searchtype=author&query=Linton%2C+M">Mark Linton</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</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=Long%2C+D">David Long</a>, <a href="/search/astro-ph?searchtype=author&query=Leake%2C+J">James Leake</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="1807.00020v1-abstract-short" style="display: inline;"> We describe and analyze observations by the Solar Dynamics Observatory of the emergence of a small, bipolar active region within an area of unipolar magnetic flux that was surrounded by a circular, quiescent filament. Within only eight hours of the start of the emergence, a partial splitting of the filament and two consecutive coronal mass ejections took place. We argue that all three dynamic even… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.00020v1-abstract-full').style.display = 'inline'; document.getElementById('1807.00020v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1807.00020v1-abstract-full" style="display: none;"> We describe and analyze observations by the Solar Dynamics Observatory of the emergence of a small, bipolar active region within an area of unipolar magnetic flux that was surrounded by a circular, quiescent filament. Within only eight hours of the start of the emergence, a partial splitting of the filament and two consecutive coronal mass ejections took place. We argue that all three dynamic events occurred as a result of particular magnetic-reconnection episodes between the emerging bipole and the pre-existing coronal magnetic field. In order to substantiate our interpretation, we consider three-dimensional magnetohydrodynamic simulations that model the emergence of magnetic flux in the vicinity of a large-scale coronal flux rope. The simulations qualitatively reproduce most of the reconnection episodes suggested by the observations; as well as the filament-splitting, the first eruption, and the formation of sheared/twisted fields that may have played a role in the second eruption. Our results suggest that the position of emerging flux with respect to the background magnetic configuration is a crucial factor for the resulting evolution, while previous results suggest that parameters such as the orientation or the amount of emerging flux are important as well. This poses a challenge for predicting the onset of eruptions that are triggered by flux emergence, and it calls for a detailed survey of the relevant parameter space by means of numerical simulations. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1807.00020v1-abstract-full').style.display = 'none'; document.getElementById('1807.00020v1-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> 29 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">17 pages, 8 figures, accepted for publication by 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/1806.05374">arXiv:1806.05374</a> <span> [<a href="https://arxiv.org/pdf/1806.05374">pdf</a>, <a href="https://arxiv.org/format/1806.05374">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/aad9fb">10.3847/1538-4357/aad9fb <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Identifying Observables that can Differentiate Between Impulsive and Footpoint Heating: Time Lags and Intensity Ratios </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Winebarger%2C+A+R">Amy R. Winebarger</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Mikic%2C+Z">Zoran Mikic</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J">Jon Linker</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="1806.05374v2-abstract-short" style="display: inline;"> Observations of coronal loops have identified several common loop characteristics, including that loops appear to cool and have higher than expected densities. Two potential heating scenarios have been suggested to explain these observations. One scenario is that the loops are heated by a series of small-scale impulsive heating events, or nanoflares. Another hypothesis is that the heating is quasi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.05374v2-abstract-full').style.display = 'inline'; document.getElementById('1806.05374v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1806.05374v2-abstract-full" style="display: none;"> Observations of coronal loops have identified several common loop characteristics, including that loops appear to cool and have higher than expected densities. Two potential heating scenarios have been suggested to explain these observations. One scenario is that the loops are heated by a series of small-scale impulsive heating events, or nanoflares. Another hypothesis is that the heating is quasi-steady and highly-stratified, i.e., ``footpoint heating'. The goal of this paper is to identify observables that can be used to differentiate between these two heating scenarios. For footpoint heating, we vary the heating magnitude and stratification, for impulsive heating, we vary the heating magnitude. We use one-dimensional hydrodynamic codes to calculate the resulting temperature and density evolution and expected lightcurves in four channels of AIA and one channel of XRT. We consider two principal diagnostics: the time lag between the appearance of the loop in two different channels, and the ratio of the peak intensities of the loop in the two channels. We find that 1) footpoint heating can predict longer time lags than impulsive heating, 2) footpoint heating can predict zero or negative time lags, 3) the intensity ratio expected from impulsive heating is confined to a narrow range, while footpoint heating predicts a wider range of intensity ratios, and 4) the range of temperatures expected in impulsive heating is broader than the range of temperatures expected in footpoint heating. This preliminary study identifies observables that may be useful in discriminating between heating models in future work. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1806.05374v2-abstract-full').style.display = 'none'; document.getElementById('1806.05374v2-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> 11 September, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 June, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2018. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1801.05903">arXiv:1801.05903</a> <span> [<a href="https://arxiv.org/pdf/1801.05903">pdf</a>, <a href="https://arxiv.org/format/1801.05903">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/aab36d">10.3847/1538-4357/aab36d <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Sun-to-Earth MHD Simulation of the 14 July 2000 "Bastille Day" Eruption </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">Viacheslav S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Zoran Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">Pete Riley</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ron M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Wijaya%2C+J">Janvier Wijaya</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="1801.05903v1-abstract-short" style="display: inline;"> Solar eruptions are the main driver of space-weather disturbances at the Earth. Extreme events are of particular interest, not only because of the scientific challenges they pose, but also because of their possible societal consequences. Here we present a magnetohydrodynamic (MHD) simulation of the 14 July 2000 Bastille Day eruption, which produced a very strong geomagnetic storm. After constructi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.05903v1-abstract-full').style.display = 'inline'; document.getElementById('1801.05903v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1801.05903v1-abstract-full" style="display: none;"> Solar eruptions are the main driver of space-weather disturbances at the Earth. Extreme events are of particular interest, not only because of the scientific challenges they pose, but also because of their possible societal consequences. Here we present a magnetohydrodynamic (MHD) simulation of the 14 July 2000 Bastille Day eruption, which produced a very strong geomagnetic storm. After constructing a thermodynamic MHD model of the corona and solar wind, we insert a magnetically stable flux rope along the polarity inversion line of the eruption's source region and initiate the eruption by boundary flows. More than 10^33 ergs of magnetic energy are released in the eruption within a few minutes, driving a flare, an EUV wave, and a coronal mass ejection (CME) that travels in the outer corona at about 1500 km/s, close to the observed speed. We then propagate the CME to Earth, using a heliospheric MHD code. Our simulation thus provides the opportunity to test how well in situ observations of extreme events are matched if the eruption is initiated from a stable magnetic-equilibrium state. We find that the flux-rope center is very similar in character to the observed magnetic cloud, but arrives about 8.5 hours later and about 15 degrees too far to the North, with field strengths that are too weak by a factor of about 1.6. The front of the flux rope is highly distorted, exhibiting localized magnetic-field concentrations as it passes 1 AU. We discuss these properties with regard to the development of space-weather predictions based on MHD simulations of solar eruptions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1801.05903v1-abstract-full').style.display = 'none'; document.getElementById('1801.05903v1-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> 17 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">27 pages, 13 figures, under revision 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/1712.06708">arXiv:1712.06708</a> <span> [<a href="https://arxiv.org/pdf/1712.06708">pdf</a>, <a href="https://arxiv.org/format/1712.06708">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/aaa3da">10.3847/2041-8213/aaa3da <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Regularized Biot-Savart Laws for Modeling Magnetic Flux Ropes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Titov%2C+V+S">Viacheslav S. Titov</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Zoran Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=T%C3%B6r%C3%B6k%2C+T">Tibor T枚r枚k</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">Ronald M. Caplan</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="1712.06708v1-abstract-short" style="display: inline;"> Many existing models assume that magnetic flux ropes play a key role in solar flares and coronal mass ejections (CMEs). It is therefore important to develop efficient methods for constructing flux-rope configurations constrained by observed magnetic data and the morphology of the pre-eruptive source region. For this purpose, we have derived and implemented a compact analytical form that represents… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.06708v1-abstract-full').style.display = 'inline'; document.getElementById('1712.06708v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.06708v1-abstract-full" style="display: none;"> Many existing models assume that magnetic flux ropes play a key role in solar flares and coronal mass ejections (CMEs). It is therefore important to develop efficient methods for constructing flux-rope configurations constrained by observed magnetic data and the morphology of the pre-eruptive source region. For this purpose, we have derived and implemented a compact analytical form that represents the magnetic field of a thin flux rope with an axis of arbitrary shape and circular cross-sections. This form implies that the flux rope carries axial current $I$ and axial flux $F$, so that the respective magnetic field is the curl of the sum of axial and azimuthal vector potentials proportional to $I$ and $F$, respectively. We expressed the vector potentials in terms of modified Biot-Savart laws whose kernels are regularized at the axis in such a way that, when the axis is straight, these laws define a cylindrical force-free flux rope with a parabolic profile for the axial current density. For the cases we have studied so far, we determined the shape of the rope axis by following the polarity inversion line of the eruptions' source region, using observed magnetograms. The height variation along the axis and other flux-rope parameters are estimated by means of potential field extrapolations. Using this heuristic approach, we were able to construct pre-eruption configurations for the 2009 February 13 and 2011 October 1 CME events. These applications demonstrate the flexibility and efficiency of our new method for energizing pre-eruptive configurations in simulations of CMEs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.06708v1-abstract-full').style.display = 'none'; document.getElementById('1712.06708v1-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 December, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2017. </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 with 5 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/1708.02342">arXiv:1708.02342</a> <span> [<a href="https://arxiv.org/pdf/1708.02342">pdf</a>, <a href="https://arxiv.org/format/1708.02342">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/aa8a70">10.3847/1538-4357/aa8a70 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Open Flux Problem </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">J. A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Caplan%2C+R+M">R. M. Caplan</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">C. Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Riley%2C+P">P Riley</a>, <a href="/search/astro-ph?searchtype=author&query=Mikic%2C+Z">Z Mikic</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">R. Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Henney%2C+C+J">C. J. Henney</a>, <a href="/search/astro-ph?searchtype=author&query=Arge%2C+C+N">C. N. Arge</a>, <a href="/search/astro-ph?searchtype=author&query=Liu%2C+Y">Y. Liu</a>, <a href="/search/astro-ph?searchtype=author&query=Derosa%2C+M+L">M. L. Derosa</a>, <a href="/search/astro-ph?searchtype=author&query=Yeates%2C+A">A. Yeates</a>, <a href="/search/astro-ph?searchtype=author&query=Owens%2C+M+J">M. J. Owens</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="1708.02342v2-abstract-short" style="display: inline;"> The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun's photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field reg… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.02342v2-abstract-full').style.display = 'inline'; document.getElementById('1708.02342v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1708.02342v2-abstract-full" style="display: none;"> The heliospheric magnetic field is of pivotal importance in solar and space physics. The field is rooted in the Sun's photosphere, where it has been observed for many years. Global maps of the solar magnetic field based on full disk magnetograms are commonly used as boundary conditions for coronal and solar wind models. Two primary observational constraints on the models are (1) the open field regions in the model should approximately correspond to coronal holes observed in emission, and (2) the magnitude of the open magnetic flux in the model should match that inferred from in situ spacecraft measurements. In this study, we calculate both MHD and PFSS solutions using fourteen different magnetic maps produced from five different types of observatory magnetograms, for the time period surrounding July, 2010. We have found that for all of the model/map combinations, models that have coronal hole areas close to observations underestimate the interplanetary magnetic flux, or, conversely, for models to match the interplanetary flux, the modeled open field regions are larger than coronal holes observed in EUV emission. In an alternative approach, we estimate the open magnetic flux entirely from solar observations by combining automatically detected coronal holes for Carrington rotation 2098 with observatory synoptic magnetic maps. This approach also underestimates the interplanetary magnetic flux. Our results imply that either typical observatory maps underestimate the Sun's magnetic flux, or a significant portion of the open magnetic flux is not rooted in regions that are obviously dark in EUV and X-ray emission. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1708.02342v2-abstract-full').style.display = 'none'; document.getElementById('1708.02342v2-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, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 7 August, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1706.06967">arXiv:1706.06967</a> <span> [<a href="https://arxiv.org/pdf/1706.06967">pdf</a>, <a href="https://arxiv.org/format/1706.06967">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> </div> </div> <p class="title is-5 mathjax"> MinXSS-1 CubeSat On-Orbit Pointing and Power Performance: The First Flight of the Blue Canyon Technologies XACT 3-axis Attitude Determination and Control System </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Mason%2C+J+P">James Paul Mason</a>, <a href="/search/astro-ph?searchtype=author&query=Baumgart%2C+M">Matt Baumgart</a>, <a href="/search/astro-ph?searchtype=author&query=Rogler%2C+B">Bryan Rogler</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Chloe Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Williams%2C+M">Margaret Williams</a>, <a href="/search/astro-ph?searchtype=author&query=Woods%2C+T+N">Thomas N. Woods</a>, <a href="/search/astro-ph?searchtype=author&query=Palo%2C+S">Scott Palo</a>, <a href="/search/astro-ph?searchtype=author&query=Chamberlin%2C+P+C">Phillip C. Chamberlin</a>, <a href="/search/astro-ph?searchtype=author&query=Solomon%2C+S">Stanley Solomon</a>, <a href="/search/astro-ph?searchtype=author&query=Jones%2C+A">Andrew Jones</a>, <a href="/search/astro-ph?searchtype=author&query=Li%2C+X">Xinlin Li</a>, <a href="/search/astro-ph?searchtype=author&query=Kohnert%2C+R">Rick Kohnert</a>, <a href="/search/astro-ph?searchtype=author&query=Caspi%2C+A">Amir Caspi</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="1706.06967v2-abstract-short" style="display: inline;"> The Miniature X-ray Solar Spectrometer (MinXSS) is a 3 Unit (3U) CubeSat designed for a 3-month mission to study solar soft X-ray spectral irradiance. The first of the two flight models was deployed from the International Space Station in 2016 May and operated for one year before its natural deorbiting. This was the first flight of the Blue Canyon Technologies XACT 3-axis attitude determination an… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.06967v2-abstract-full').style.display = 'inline'; document.getElementById('1706.06967v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1706.06967v2-abstract-full" style="display: none;"> The Miniature X-ray Solar Spectrometer (MinXSS) is a 3 Unit (3U) CubeSat designed for a 3-month mission to study solar soft X-ray spectral irradiance. The first of the two flight models was deployed from the International Space Station in 2016 May and operated for one year before its natural deorbiting. This was the first flight of the Blue Canyon Technologies XACT 3-axis attitude determination and control system -- a commercially available, high-precision pointing system. We characterized the performance of the pointing system on orbit including performance at low altitudes where drag torque builds up. We found that the pointing accuracy was 0.0042\degree\ - 0.0117\degree\ (15$''$ - 42$''$, 3$蟽$, axis dependent) consistently from 190 km - 410 km, slightly better than the specification sheet states. Peak-to-peak jitter was estimated to be 0.0073\degree\ (10 s$^{-1}$) - 0.0183\degree\ (10 s$^{-1}$) (26$''$ (10 s$^{-1}$) - 66$''$ (10 s$^{-1}$), 3$蟽$). The system was capable of dumping momentum until an altitude of 185 km. We found small amounts of sensor degradation in the star tracker and coarse sun sensor. Our mission profile did not require high-agility maneuvers so we are unable to characterize this metric. Without a GPS receiver, it was necessary to periodically upload ephemeris information to update the orbit propagation model and maintain pointing. At 400 km, these uploads were required once every other week. At $\sim$270 km, they were required every day. We also characterized the power performance of our electric power system, which includes a novel pseudo-peak power tracker -- a resistor that limited the current draw from the battery on the solar panels. With 19 30\% efficient solar cells and an 8 W system load, the power balance had 65\% of margin on orbit. We present several recommendations to other CubeSat programs throughout. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1706.06967v2-abstract-full').style.display = 'none'; document.getElementById('1706.06967v2-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 November, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 21 June, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2017. </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, 16 figures, accepted at Journal of Small Satellites</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Small Satellites, Vol. 6, Issue 3, pp. 651-662; 2017 December </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1611.05505">arXiv:1611.05505</a> <span> [<a href="https://arxiv.org/pdf/1611.05505">pdf</a>, <a href="https://arxiv.org/format/1611.05505">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/s11207-016-1030-y">10.1007/s11207-016-1030-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Understanding the Physical Nature of Coronal "EIT Waves" </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=Bloomfield%2C+D+S">D. Shaun Bloomfield</a>, <a href="/search/astro-ph?searchtype=author&query=Chen%2C+P">Peng-Fei Chen</a>, <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</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=Kwon%2C+R+Y">Ryun Young Kwon</a>, <a href="/search/astro-ph?searchtype=author&query=Vanninathan%2C+K">Kamalam Vanninathan</a>, <a href="/search/astro-ph?searchtype=author&query=Veronig%2C+A+M">Astrid M. Veronig</a>, <a href="/search/astro-ph?searchtype=author&query=Vourlidas%2C+A">Angelos Vourlidas</a>, <a href="/search/astro-ph?searchtype=author&query=Vrsnak%2C+B">Bojan Vrsnak</a>, <a href="/search/astro-ph?searchtype=author&query=Warmuth%2C+A">Alexander Warmuth</a>, <a href="/search/astro-ph?searchtype=author&query=Zic%2C+T">Tomislav Zic</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="1611.05505v1-abstract-short" style="display: inline;"> For almost 20 years the physical nature of globally propagating waves in the solar corona (commonly called "EIT waves") has been controversial and subject to debate. Additional theories have been proposed over the years to explain observations that did not fit with the originally proposed fast-mode wave interpretation. However, the incompatibility of observations made using the Extreme-ultraviolet… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.05505v1-abstract-full').style.display = 'inline'; document.getElementById('1611.05505v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1611.05505v1-abstract-full" style="display: none;"> For almost 20 years the physical nature of globally propagating waves in the solar corona (commonly called "EIT waves") has been controversial and subject to debate. Additional theories have been proposed over the years to explain observations that did not fit with the originally proposed fast-mode wave interpretation. However, the incompatibility of observations made using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory with the fast-mode wave interpretation was challenged by differing viewpoints from the twin Solar Terrestrial Relations Observatory spacecraft and higher spatial/temporal resolution data from the Solar Dynamics Observatory. In this article, we reexamine the theories proposed to explain "EIT waves" to identify measurable properties and behaviours that can be compared to current and future observations. Most of us conclude that "EIT waves" are best described as fast-mode large-amplitude waves/shocks that are initially driven by the impulsive expansion of an erupting coronal mass ejection in the low corona. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1611.05505v1-abstract-full').style.display = 'none'; document.getElementById('1611.05505v1-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 November, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2016. </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, 2 figures, accepted for publication in Solar 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/1610.02113">arXiv:1610.02113</a> <span> [<a href="https://arxiv.org/pdf/1610.02113">pdf</a>, <a href="https://arxiv.org/format/1610.02113">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/10.3847/0004-637X/832/2/180">10.3847/0004-637X/832/2/180 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Closed-Field Coronal Heating Driven by Wave Turbulence </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/astro-ph?searchtype=author&query=Downs%2C+C">Cooper Downs</a>, <a href="/search/astro-ph?searchtype=author&query=Lionello%2C+R">Roberto Lionello</a>, <a href="/search/astro-ph?searchtype=author&query=Miki%C4%87%2C+Z">Zoran Miki膰</a>, <a href="/search/astro-ph?searchtype=author&query=Linker%2C+J+A">Jon A. Linker</a>, <a href="/search/astro-ph?searchtype=author&query=Velli%2C+M">Marco Velli</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="1610.02113v1-abstract-short" style="display: inline;"> To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence-driven (WTD) phenomenology for the heating of closed coronal loops. Our implementation is designed to ca… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.02113v1-abstract-full').style.display = 'inline'; document.getElementById('1610.02113v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1610.02113v1-abstract-full" style="display: none;"> To simulate the energy balance of coronal plasmas on macroscopic scales, we often require the specification of the coronal heating mechanism in some functional form. To go beyond empirical formulations and to build a more physically motivated heating function, we investigate the wave-turbulence-driven (WTD) phenomenology for the heating of closed coronal loops. Our implementation is designed to capture the large-scale propagation, reflection, and dissipation of wave turbulence along a loop. The parameter space of this model is explored by solving the coupled WTD and hydrodynamic evolution in 1D for an idealized loop. The relevance to a range of solar conditions is also established by computing solutions for over one hundred loops extracted from a realistic 3D coronal field. Due to the implicit dependence of the WTD heating model on loop geometry and plasma properties along the loop and at the footpoints, we find that this model can significantly reduce the number of free parameters when compared to traditional empirical heating models, and still robustly describe a broad range of quiet-sun and active region conditions. The importance of the self-reflection term in producing relatively short heating scale heights and thermal nonequilibrium cycles is also discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1610.02113v1-abstract-full').style.display = 'none'; document.getElementById('1610.02113v1-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> 6 October, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2016. </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 ApJ, September 30, 2016</span> </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 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