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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=Thomas%2C+B&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Thomas%2C+B&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Thomas%2C+B&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <ol class="breathe-horizontal" start="1"> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2411.14605">arXiv:2411.14605</a> <span> [<a href="https://arxiv.org/pdf/2411.14605">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Physics Education">physics.ed-ph</span> </div> </div> <p class="title is-5 mathjax"> The effect of color-coding on students' perception of learning in introductory mechanics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+S+D">Brianna S. Dillon Thomas</a>, <a href="/search/physics?searchtype=author&query=Carr%2C+S">Scott Carr</a>, <a href="/search/physics?searchtype=author&query=Guo%2C+S">Siming Guo</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2411.14605v1-abstract-short" style="display: inline;"> We designed three color-coding schemes to identify related information across representations and to differentiate distinct information within a representation in slide-based instruction for calculus-based introductory mechanics. We found that students had generally favorable opinions on the use of color and that the few negative criticisms are easily addressed through minor modifications to imple… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.14605v1-abstract-full').style.display = 'inline'; document.getElementById('2411.14605v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2411.14605v1-abstract-full" style="display: none;"> We designed three color-coding schemes to identify related information across representations and to differentiate distinct information within a representation in slide-based instruction for calculus-based introductory mechanics. We found that students had generally favorable opinions on the use of color and that the few negative criticisms are easily addressed through minor modifications to implementation. Without having the color-coding schemes pointed out to them, a modest but consistent minority of students who found color helpful also described the color-coding schemes implemented, and about a quarter described the use of color in physics contexts as helpful even if they did not describe color-coding. We found that students particularly favored using color in mathematics and color-coding used to identify related variables, verbal definitions, and diagram elements. We additionally found that on average 40% of students found color to be helpful in matching and connecting related information or in separating and distinguishing distinct information, which were the motivating reasons for employing the color-coding schemes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2411.14605v1-abstract-full').style.display = 'none'; document.getElementById('2411.14605v1-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 November, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2409.06832">arXiv:2409.06832</a> <span> [<a href="https://arxiv.org/pdf/2409.06832">pdf</a>, <a href="https://arxiv.org/format/2409.06832">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2024GL110174">10.1029/2024GL110174 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Earth's Mesosphere During Possible Encounters With Massive Interstellar Clouds 2 and 7 Million Years Ago </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Miller%2C+J+A">Jesse A. Miller</a>, <a href="/search/physics?searchtype=author&query=Opher%2C+M">Merav Opher</a>, <a href="/search/physics?searchtype=author&query=Hatzaki%2C+M">Maria Hatzaki</a>, <a href="/search/physics?searchtype=author&query=Papachristopoulou%2C+K">Kyriakoula Papachristopoulou</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="2409.06832v1-abstract-short" style="display: inline;"> Our solar system's path has recently been shown to potentially intersect dense interstellar clouds 2 and 7 million years ago: the Local Lynx of Cold Cloud and the edge of the Local Bubble. These clouds compressed the heliosphere, directly exposing Earth to the interstellar medium. Previous studies that examined climate effects of these encounters argued for an induced ice age due to the formation… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06832v1-abstract-full').style.display = 'inline'; document.getElementById('2409.06832v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2409.06832v1-abstract-full" style="display: none;"> Our solar system's path has recently been shown to potentially intersect dense interstellar clouds 2 and 7 million years ago: the Local Lynx of Cold Cloud and the edge of the Local Bubble. These clouds compressed the heliosphere, directly exposing Earth to the interstellar medium. Previous studies that examined climate effects of these encounters argued for an induced ice age due to the formation of global noctilucent clouds (NLCs). Here, we revisit such studies with a modern 2D atmospheric chemistry model using parameters of global heliospheric magnetohydrodynamic models as input. We show that NLCs remain confined to polar latitudes and short seasonal lifetimes during these dense cloud crossings lasting $\sim10^5$ years. Polar mesospheric ozone becomes significantly depleted, but the total ozone column broadly increases. Furthermore, we show that the densest NLCs lessen the amount of sunlight reaching the surface instantaneously by up to 7% while halving outgoing longwave radiation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2409.06832v1-abstract-full').style.display = 'none'; document.getElementById('2409.06832v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 10 September, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 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">12 pages, 4 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Geophysical Research Letters, volume 51, issue 17, id e2024GL110174 (7 September 2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2408.10179">arXiv:2408.10179</a> <span> [<a href="https://arxiv.org/pdf/2408.10179">pdf</a>, <a href="https://arxiv.org/format/2408.10179">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1038/s41467-024-51412-8">10.1038/s41467-024-51412-8 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Three-stage Formation of Cap Carbonates after Marinoan Snowball Glaciation Consistent with Depositional Timescales and Geochemistry </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+T+B">Trent B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Catling%2C+D+C">David C. Catling</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="2408.10179v1-abstract-short" style="display: inline;"> At least two global "Snowball Earth" glaciations occurred during the Neoproterozoic Era (1000-538.8 million years ago). Post-glacial surface environments during this time are recorded in cap carbonates: layers of limestone or dolostone that directly overlie glacial deposits. Postulated environmental conditions that created the cap carbonates lack consensus largely because single hypotheses fail to… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10179v1-abstract-full').style.display = 'inline'; document.getElementById('2408.10179v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2408.10179v1-abstract-full" style="display: none;"> At least two global "Snowball Earth" glaciations occurred during the Neoproterozoic Era (1000-538.8 million years ago). Post-glacial surface environments during this time are recorded in cap carbonates: layers of limestone or dolostone that directly overlie glacial deposits. Postulated environmental conditions that created the cap carbonates lack consensus largely because single hypotheses fail to explain the cap carbonates' global mass, depositional timescales, and geochemistry of parent waters. Here, we present a global geologic carbon cycle model before, during, and after the second glaciation (i.e. the Marinoan) that explains cap carbonate characteristics. We find a three-stage process for cap carbonate formation: (1) low-temperature seafloor weathering during glaciation generates deep-sea alkalinity; (2) vigorous post-glacial continental weathering supplies alkalinity to a carbonate-saturated freshwater layer, rapidly precipitating cap carbonates; (3) mixing of post-glacial meltwater with deep-sea alkalinity prolongs cap carbonate deposition. We suggest how future geochemical data and modeling refinements could further assess our hypothesis. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2408.10179v1-abstract-full').style.display = 'none'; document.getElementById('2408.10179v1-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 August, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">Main text is 30 pages double spaced. 8 figures, 1 table. Supplementary Material included at end of file. Published in Nature Communications</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Nat Commun 15, 7055 (2024) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2404.19374">arXiv:2404.19374</a> <span> [<a href="https://arxiv.org/pdf/2404.19374">pdf</a>, <a href="https://arxiv.org/format/2404.19374">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 Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> Perspectives of a single-anode cylindrical chamber operating in ionization mode and high gas pressure </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Bouet%2C+R">R. Bouet</a>, <a href="/search/physics?searchtype=author&query=Busto%2C+J">J. Busto</a>, <a href="/search/physics?searchtype=author&query=Cecchini%2C+V">V. Cecchini</a>, <a href="/search/physics?searchtype=author&query=Charpentier%2C+P">P. Charpentier</a>, <a href="/search/physics?searchtype=author&query=Chapellier%2C+M">M. Chapellier</a>, <a href="/search/physics?searchtype=author&query=Dastgheibi-Fard%2C+A">A. Dastgheibi-Fard</a>, <a href="/search/physics?searchtype=author&query=Druillole%2C+F">F. Druillole</a>, <a href="/search/physics?searchtype=author&query=Jollet%2C+C">C. Jollet</a>, <a href="/search/physics?searchtype=author&query=Hellmuth%2C+P">P. Hellmuth</a>, <a href="/search/physics?searchtype=author&query=Gros%2C+M">M. Gros</a>, <a href="/search/physics?searchtype=author&query=Lautridou%2C+P">P. Lautridou</a>, <a href="/search/physics?searchtype=author&query=Meregaglia%2C+A">A. Meregaglia</a>, <a href="/search/physics?searchtype=author&query=Navick%2C+X+F">X. F. Navick</a>, <a href="/search/physics?searchtype=author&query=Piquemal%2C+F">F. Piquemal</a>, <a href="/search/physics?searchtype=author&query=Roche%2C+M">M. Roche</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B. Thomas</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="2404.19374v1-abstract-short" style="display: inline;"> As part of the R2D2 (Rare Decays with Radial Detector) R&D, the use of a gas detector with a spherical or cylindrical cathode, equipped with a single anode and operating at high pressure, was studied for the search of rare phenomena such as neutrinoless double-beta decay. The presented measurements were obtained with a cylindrical detector, covering gas pressures ranging from 1 to 10 bar in argon… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.19374v1-abstract-full').style.display = 'inline'; document.getElementById('2404.19374v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2404.19374v1-abstract-full" style="display: none;"> As part of the R2D2 (Rare Decays with Radial Detector) R&D, the use of a gas detector with a spherical or cylindrical cathode, equipped with a single anode and operating at high pressure, was studied for the search of rare phenomena such as neutrinoless double-beta decay. The presented measurements were obtained with a cylindrical detector, covering gas pressures ranging from 1 to 10 bar in argon and 1 to 6 bar in xenon, using both a point-like source of $^{210}$Po (5.3 MeV $伪$ ) and a diffuse source of $^{222}$Rn (5.5 MeV $伪$). Analysis and interpretation of the data were developed using the anodic current waveform. Similar detection performances were achieved with both gases, and comparable energy resolutions were measured with both sources. As long as the purity of the gas was sufficient, no significant degradation of the measured energy was observed by increasing the pressure. At the highest operating pressure, an energy resolution better than 1.5% full-width at half-maximum (FWHM) was obtained for both gaseous media, although optimal noise conditions were not reached. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2404.19374v1-abstract-full').style.display = 'none'; document.getElementById('2404.19374v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 April, 2024; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2024. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2309.13637">arXiv:2309.13637</a> <span> [<a href="https://arxiv.org/pdf/2309.13637">pdf</a>, <a href="https://arxiv.org/format/2309.13637">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 Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> </div> </div> <p class="title is-5 mathjax"> R2D2 TPC: first Xenon results </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Bouet%2C+R">R. Bouet</a>, <a href="/search/physics?searchtype=author&query=Busto%2C+J">J. Busto</a>, <a href="/search/physics?searchtype=author&query=Cecchini%2C+V">V. Cecchini</a>, <a href="/search/physics?searchtype=author&query=Cerna%2C+C">C. Cerna</a>, <a href="/search/physics?searchtype=author&query=Charpentier%2C+P">P. Charpentier</a>, <a href="/search/physics?searchtype=author&query=Chapellier%2C+M">M. Chapellier</a>, <a href="/search/physics?searchtype=author&query=Dastgheibi-Fard%2C+A">A. Dastgheibi-Fard</a>, <a href="/search/physics?searchtype=author&query=Druillole%2C+F">F. Druillole</a>, <a href="/search/physics?searchtype=author&query=Jollet%2C+C">C. Jollet</a>, <a href="/search/physics?searchtype=author&query=Hellmuth%2C+P">P. Hellmuth</a>, <a href="/search/physics?searchtype=author&query=Gros%2C+M">M. Gros</a>, <a href="/search/physics?searchtype=author&query=Lautridou%2C+P">P. Lautridou</a>, <a href="/search/physics?searchtype=author&query=Meregaglia%2C+A">A. Meregaglia</a>, <a href="/search/physics?searchtype=author&query=Navick%2C+X+F">X. F. Navick</a>, <a href="/search/physics?searchtype=author&query=Piquemal%2C+F">F. Piquemal</a>, <a href="/search/physics?searchtype=author&query=Popieul%2C+F">F. Popieul</a>, <a href="/search/physics?searchtype=author&query=Roche%2C+M">M. Roche</a>, <a href="/search/physics?searchtype=author&query=Savvidis%2C+I">I. Savvidis</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B. Thomas</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="2309.13637v1-abstract-short" style="display: inline;"> Radial time projection chambers (TPC), already employed in the search for rare phenomena such as light Dark Matter candidate, could provide a new detection approach for the search of neutrinoless double beta decay ($尾\beta0谓$). The assessment of the performances of such a detector for $尾\beta0谓$ search is indeed the goal of the Rare Decays with Radial Detector (R2D2) R\&D. Promising results operat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.13637v1-abstract-full').style.display = 'inline'; document.getElementById('2309.13637v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2309.13637v1-abstract-full" style="display: none;"> Radial time projection chambers (TPC), already employed in the search for rare phenomena such as light Dark Matter candidate, could provide a new detection approach for the search of neutrinoless double beta decay ($尾\beta0谓$). The assessment of the performances of such a detector for $尾\beta0谓$ search is indeed the goal of the Rare Decays with Radial Detector (R2D2) R\&D. Promising results operating a spherical TPC with argon up to 1~bar have been published in 2021. Supplementary measurements were recently taken extending the gas pressure range up to 3~bar. In addition, a comparison between two detector geometries, namely spherical (SPC for spherical proportional counter) and cylindrical (CPC for cylindrical proportional counter), was performed. Using a relatively simple gas purification system the CPC detector was also operated with xenon at 1~bar: an energy resolution of 1.4\% full-width at half-maximum was achieved for drift distances up to 17~cm. Much lower resolution was observed with the SPC. These results are presented in this article. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2309.13637v1-abstract-full').style.display = 'none'; document.getElementById('2309.13637v1-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 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">16 pages 14 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2304.07348">arXiv:2304.07348</a> <span> [<a href="https://arxiv.org/pdf/2304.07348">pdf</a>, <a href="https://arxiv.org/format/2304.07348">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="Cosmology and Nongalactic Astrophysics">astro-ph.CO</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</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/accdd0">10.3847/1538-4357/accdd0 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Using Dark Energy Explorers and Machine Learning to Enhance the Hobby-Eberly Telescope Dark Energy Experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=House%2C+L+R">Lindsay R. House</a>, <a href="/search/physics?searchtype=author&query=Gebhardt%2C+K">Karl Gebhardt</a>, <a href="/search/physics?searchtype=author&query=Finkelstein%2C+K">Keely Finkelstein</a>, <a href="/search/physics?searchtype=author&query=Cooper%2C+E+M">Erin Mentuch Cooper</a>, <a href="/search/physics?searchtype=author&query=Davis%2C+D">Dustin Davis</a>, <a href="/search/physics?searchtype=author&query=Ciardullo%2C+R">Robin Ciardullo</a>, <a href="/search/physics?searchtype=author&query=Farrow%2C+D+J">Daniel J Farrow</a>, <a href="/search/physics?searchtype=author&query=Finkelstein%2C+S+L">Steven L. Finkelstein</a>, <a href="/search/physics?searchtype=author&query=Gronwall%2C+C">Caryl Gronwall</a>, <a href="/search/physics?searchtype=author&query=Jeong%2C+D">Donghui Jeong</a>, <a href="/search/physics?searchtype=author&query=Johnson%2C+L+C">L. Clifton Johnson</a>, <a href="/search/physics?searchtype=author&query=Liu%2C+C">Chenxu Liu</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+P">Benjamin P. Thomas</a>, <a href="/search/physics?searchtype=author&query=Zeimann%2C+G">Gregory Zeimann</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2304.07348v1-abstract-short" style="display: inline;"> We present analysis using a citizen science campaign to improve the cosmological measures from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the Hubble expansion rate, $H(z)$, and angular diameter distance, $D_A(z)$, at $z =$ 2.4, each to percent-level accuracy. This accuracy is determined primarily from the total number of detected Lyman-$伪$ emitters… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.07348v1-abstract-full').style.display = 'inline'; document.getElementById('2304.07348v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2304.07348v1-abstract-full" style="display: none;"> We present analysis using a citizen science campaign to improve the cosmological measures from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX). The goal of HETDEX is to measure the Hubble expansion rate, $H(z)$, and angular diameter distance, $D_A(z)$, at $z =$ 2.4, each to percent-level accuracy. This accuracy is determined primarily from the total number of detected Lyman-$伪$ emitters (LAEs), the false positive rate due to noise, and the contamination due to [O II] emitting galaxies. This paper presents the citizen science project, Dark Energy Explorers, with the goal of increasing the number of LAEs, decreasing the number of false positives due to noise and the [O II] galaxies. Initial analysis shows that citizen science is an efficient and effective tool for classification most accurately done by the human eye, especially in combination with unsupervised machine learning. Three aspects from the citizen science campaign that have the most impact are 1) identifying individual problems with detections, 2) providing a clean sample with 100% visual identification above a signal-to-noise cut, and 3) providing labels for machine learning efforts. Since the end of 2022, Dark Energy Explorers has collected over three and a half million classifications by 11,000 volunteers in over 85 different countries around the world. By incorporating the results of the Dark Energy Explorers we expect to improve the accuracy on the $D_A(z)$ and $H(z)$ parameters at $z =$ 2.4 by 10 - 30%. While the primary goal is to improve on HETDEX, Dark Energy Explorers has already proven to be a uniquely powerful tool for science advancement and increasing accessibility to science worldwide. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2304.07348v1-abstract-full').style.display = 'none'; document.getElementById('2304.07348v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 April, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">14 pages, 6 figures, accepted for publication in The Astrophysical Journal</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.08533">arXiv:2303.08533</a> <span> [<a href="https://arxiv.org/pdf/2303.08533">pdf</a>, <a href="https://arxiv.org/format/2303.08533">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Accelerator Physics">physics.acc-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> Towards a Muon Collider </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Accettura%2C+C">Carlotta Accettura</a>, <a href="/search/physics?searchtype=author&query=Adams%2C+D">Dean Adams</a>, <a href="/search/physics?searchtype=author&query=Agarwal%2C+R">Rohit Agarwal</a>, <a href="/search/physics?searchtype=author&query=Ahdida%2C+C">Claudia Ahdida</a>, <a href="/search/physics?searchtype=author&query=Aim%C3%A8%2C+C">Chiara Aim猫</a>, <a href="/search/physics?searchtype=author&query=Amapane%2C+N">Nicola Amapane</a>, <a href="/search/physics?searchtype=author&query=Amorim%2C+D">David Amorim</a>, <a href="/search/physics?searchtype=author&query=Andreetto%2C+P">Paolo Andreetto</a>, <a href="/search/physics?searchtype=author&query=Anulli%2C+F">Fabio Anulli</a>, <a href="/search/physics?searchtype=author&query=Appleby%2C+R">Robert Appleby</a>, <a href="/search/physics?searchtype=author&query=Apresyan%2C+A">Artur Apresyan</a>, <a href="/search/physics?searchtype=author&query=Apyan%2C+A">Aram Apyan</a>, <a href="/search/physics?searchtype=author&query=Arsenyev%2C+S">Sergey Arsenyev</a>, <a href="/search/physics?searchtype=author&query=Asadi%2C+P">Pouya Asadi</a>, <a href="/search/physics?searchtype=author&query=Mahmoud%2C+M+A">Mohammed Attia Mahmoud</a>, <a href="/search/physics?searchtype=author&query=Azatov%2C+A">Aleksandr Azatov</a>, <a href="/search/physics?searchtype=author&query=Back%2C+J">John Back</a>, <a href="/search/physics?searchtype=author&query=Balconi%2C+L">Lorenzo Balconi</a>, <a href="/search/physics?searchtype=author&query=Bandiera%2C+L">Laura Bandiera</a>, <a href="/search/physics?searchtype=author&query=Barlow%2C+R">Roger Barlow</a>, <a href="/search/physics?searchtype=author&query=Bartosik%2C+N">Nazar Bartosik</a>, <a href="/search/physics?searchtype=author&query=Barzi%2C+E">Emanuela Barzi</a>, <a href="/search/physics?searchtype=author&query=Batsch%2C+F">Fabian Batsch</a>, <a href="/search/physics?searchtype=author&query=Bauce%2C+M">Matteo Bauce</a>, <a href="/search/physics?searchtype=author&query=Berg%2C+J+S">J. Scott Berg</a> , et al. (272 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.08533v2-abstract-short" style="display: inline;"> A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders desi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08533v2-abstract-full').style.display = 'inline'; document.getElementById('2303.08533v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.08533v2-abstract-full" style="display: none;"> A muon collider would enable the big jump ahead in energy reach that is needed for a fruitful exploration of fundamental interactions. The challenges of producing muon collisions at high luminosity and 10 TeV centre of mass energy are being investigated by the recently-formed International Muon Collider Collaboration. This Review summarises the status and the recent advances on muon colliders design, physics and detector studies. The aim is to provide a global perspective of the field and to outline directions for future work. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08533v2-abstract-full').style.display = 'none'; document.getElementById('2303.08533v2-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, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 15 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">118 pages, 103 figures</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2303.08508">arXiv:2303.08508</a> <span> [<a href="https://arxiv.org/pdf/2303.08508">pdf</a>, <a href="https://arxiv.org/format/2303.08508">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</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/10.1088/1748-0221/18/03/P03031">10.1088/1748-0221/18/03/P03031 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Performance of a spherical high pressure gas TPC for neutrino magnetic moment measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Bouet%2C+R">R. Bouet</a>, <a href="/search/physics?searchtype=author&query=Busto%2C+J">J. Busto</a>, <a href="/search/physics?searchtype=author&query=Cecchini%2C+V">V. Cecchini</a>, <a href="/search/physics?searchtype=author&query=Cerna%2C+C">C. Cerna</a>, <a href="/search/physics?searchtype=author&query=Charpentier%2C+P">P. Charpentier</a>, <a href="/search/physics?searchtype=author&query=Dastgheibi-Fard%2C+A">A. Dastgheibi-Fard</a>, <a href="/search/physics?searchtype=author&query=Druillole%2C+F">F. Druillole</a>, <a href="/search/physics?searchtype=author&query=Jollet%2C+C">C. Jollet</a>, <a href="/search/physics?searchtype=author&query=Hellmuth%2C+P">P. Hellmuth</a>, <a href="/search/physics?searchtype=author&query=Katsioulas%2C+I">I. Katsioulas</a>, <a href="/search/physics?searchtype=author&query=Knights%2C+P">P. Knights</a>, <a href="/search/physics?searchtype=author&query=Giomataris%2C+I">I. Giomataris</a>, <a href="/search/physics?searchtype=author&query=Gros%2C+M">M. Gros</a>, <a href="/search/physics?searchtype=author&query=Lautridou%2C+P">P. Lautridou</a>, <a href="/search/physics?searchtype=author&query=Meregaglia%2C+A">A. Meregaglia</a>, <a href="/search/physics?searchtype=author&query=Navick%2C+X+F">X. F. Navick</a>, <a href="/search/physics?searchtype=author&query=Neep%2C+T">T. Neep</a>, <a href="/search/physics?searchtype=author&query=Nikolopoulos%2C+K">K. Nikolopoulos</a>, <a href="/search/physics?searchtype=author&query=Perrot%2C+F">F. Perrot</a>, <a href="/search/physics?searchtype=author&query=Piquemal%2C+F">F. Piquemal</a>, <a href="/search/physics?searchtype=author&query=Roche%2C+M">M. Roche</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Ward%2C+R">R. Ward</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2303.08508v1-abstract-short" style="display: inline;"> The measurement of neutrino magnetic moment larger than $10^{-19}渭_B$ would be a clear signature of physics beyond the standard model other than the existence of massive Dirac neutrinos. The use of a spherical proportional counter detector filled with gas at 40 bar located near a nuclear reactor would be a simple way to perform such a measurement exploiting the developments made on such a technolo… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08508v1-abstract-full').style.display = 'inline'; document.getElementById('2303.08508v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2303.08508v1-abstract-full" style="display: none;"> The measurement of neutrino magnetic moment larger than $10^{-19}渭_B$ would be a clear signature of physics beyond the standard model other than the existence of massive Dirac neutrinos. The use of a spherical proportional counter detector filled with gas at 40 bar located near a nuclear reactor would be a simple way to perform such a measurement exploiting the developments made on such a technology for the search of dark matter and neutrinoless double beta decay. Different targets can be used just by replacing the gas: xenon, CF$_4$ and argon were compared and the sensitivity in one year of data taking could reach the level of $4.3 \times 10^{-12} 渭_B$, $6.5 \times 10^{-12} 渭_B$, and $8.5 \times 10^{-12} 渭_B$, respectively. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2303.08508v1-abstract-full').style.display = 'none'; document.getElementById('2303.08508v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">16 pages 5 figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> 2023_JINST_18_P03031 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2302.04241">arXiv:2302.04241</a> <span> [<a href="https://arxiv.org/pdf/2302.04241">pdf</a>, <a href="https://arxiv.org/format/2302.04241">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> </div> </div> <p class="title is-5 mathjax"> Constraints on the Size and Composition of the Ancient Martian Atmosphere from Coupled CO2-N2-Ar Isotopic Evolution Models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+T+B">Trent B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Hu%2C+R">Renyu Hu</a>, <a href="/search/physics?searchtype=author&query=Lo%2C+D+Y">Daniel Y. Lo</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="2302.04241v1-abstract-short" style="display: inline;"> Present-day Mars is cold and dry, but mineralogical and morphological evidence shows that liquid-water existed on the surface of ancient Mars. In order to explain this evidence and assess ancient Mars's habitability, one must understand the size and composition of the ancient atmosphere. Here we place constraints on the ancient Martian atmosphere by modeling the coupled, self-consistent evolution… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.04241v1-abstract-full').style.display = 'inline'; document.getElementById('2302.04241v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2302.04241v1-abstract-full" style="display: none;"> Present-day Mars is cold and dry, but mineralogical and morphological evidence shows that liquid-water existed on the surface of ancient Mars. In order to explain this evidence and assess ancient Mars's habitability, one must understand the size and composition of the ancient atmosphere. Here we place constraints on the ancient Martian atmosphere by modeling the coupled, self-consistent evolution of atmospheric CO2, N2, and Ar on Mars from 3.8 billion years ago (Ga) to the present. Our model traces the evolution of these species' abundances and isotopic composition caused by atmospheric escape, volcanic outgassing, and crustal interaction. Using a Markov-Chain Monte Carlo method to explore a plausible range of parameters, we find hundreds of thousands of model solutions that recreate the modern Martian atmosphere. These solutions indicate that Mars's atmosphere contained 0.3-1.5 bar CO2 and 0.1-0.5 bar N2 at 3.8 Ga. The global volume of deposited carbonates critically determines the ancient atmospheric composition. For example, a ~1 bar CO2 ancient atmosphere with 0.2-0.4 bar N2 requires ~0.9 bar CO2 deposited in carbonates primarily in open-water systems. With the joint analysis of C, N, and Ar isotopes, we refine the constraints on the relative strengths of outgassing and sputtering, leading to an indication of a reduced early mantle from which the outgassing is sourced. Our results indicate that a CO2-N2 atmosphere with a potential H2 component on ancient Mars is consistent with Mars's geochemical evolution and may explain the evidence for its past warm and wet climate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2302.04241v1-abstract-full').style.display = 'none'; document.getElementById('2302.04241v1-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 February, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">27 pages, 11 figures, 2 tables, Accepted to The Planetary Science 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/2301.05757">arXiv:2301.05757</a> <span> [<a href="https://arxiv.org/pdf/2301.05757">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Astrophysics of Galaxies">astro-ph.GA</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="Atmospheric and Oceanic Physics">physics.ao-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/accf8a">10.3847/1538-4357/accf8a <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Terrestrial Effects of Nearby Supernovae: Updated Modeling </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Yelland%2C+A+M">Alexander M. Yelland</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2301.05757v2-abstract-short" style="display: inline;"> We have reevaluated recent studies of the effects on Earth by cosmic rays (CRs) from nearby supernovae (SNe) at 100 and 50 pc, in the diffusive transport CR case, here including an early-time suppression at lower CR energies neglected in the previous works. Inclusion of this suppression leads to lower overall CR fluxes at early times, lower atmospheric ionization, smaller resulting ozone depletion… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.05757v2-abstract-full').style.display = 'inline'; document.getElementById('2301.05757v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2301.05757v2-abstract-full" style="display: none;"> We have reevaluated recent studies of the effects on Earth by cosmic rays (CRs) from nearby supernovae (SNe) at 100 and 50 pc, in the diffusive transport CR case, here including an early-time suppression at lower CR energies neglected in the previous works. Inclusion of this suppression leads to lower overall CR fluxes at early times, lower atmospheric ionization, smaller resulting ozone depletion, and lower sea-level muon radiation doses. Differences in the atmospheric impacts are most pronounced for the 100 pc case with less significant differences in the 50 pc case. We find a greater discrepancy in the modeled sea-level muon radiation dose, with significantly smaller dose values in the 50 pc case; our results indicate it is unlikely that muon radiation is a significant threat to the biosphere for SNe beyond 20 pc, for the diffusive transport case. We have also performed new modeling of the effects of SN CRs at 20 and 10 pc. Overall, our results indicate that, considering only the effects of CRs, the "lethal" SN distance should be closer to 20 pc rather than the typically quoted 8-10 pc. Recent work on extended SN X-ray emission indicates significant effects out to 50 pc and therefore the case is now strong for increasing the standard SN lethal distance to at least 20 pc. This has implications for studies of the history of life on Earth as well as considerations of habitability in the Galaxy. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2301.05757v2-abstract-full').style.display = 'none'; document.getElementById('2301.05757v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 14 June, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 13 January, 2023; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 2023. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Replaced original version with published version</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal, Volume 950, Number 1, 2023 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2205.05115">arXiv:2205.05115</a> <span> [<a href="https://arxiv.org/pdf/2205.05115">pdf</a>, <a href="https://arxiv.org/format/2205.05115">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</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="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2023GL102958">10.1029/2023GL102958 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First High-speed Video Camera Observations of a Lightning Flash Associated with a Downward Terrestrial Gamma-ray Flash </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/physics?searchtype=author&query=Saba%2C+M+M+F">M. M. F. Saba</a>, <a href="/search/physics?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/physics?searchtype=author&query=Krehbiel%2C+P+R">P. R. Krehbiel</a>, <a href="/search/physics?searchtype=author&query=Rison%2C+W">W. Rison</a>, <a href="/search/physics?searchtype=author&query=Kieu%2C+N">N. Kieu</a>, <a href="/search/physics?searchtype=author&query=da+Silva%2C+D+R">D. R. da Silva</a>, <a href="/search/physics?searchtype=author&query=Rodeheffer%2C+D">Dan Rodeheffer</a>, <a href="/search/physics?searchtype=author&query=Stanley%2C+M+A">M. A. Stanley</a>, <a href="/search/physics?searchtype=author&query=Remington%2C+J">J. Remington</a>, <a href="/search/physics?searchtype=author&query=Mazich%2C+J">J. Mazich</a>, <a href="/search/physics?searchtype=author&query=LeVon%2C+R">R. LeVon</a>, <a href="/search/physics?searchtype=author&query=Smout%2C+K">K. Smout</a>, <a href="/search/physics?searchtype=author&query=Petrizze%2C+A">A. Petrizze</a>, <a href="/search/physics?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/physics?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/physics?searchtype=author&query=Arai%2C+Y">Y. Arai</a>, <a href="/search/physics?searchtype=author&query=Arimura%2C+R">R. Arimura</a>, <a href="/search/physics?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/physics?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/physics?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/physics?searchtype=author&query=Buckland%2C+I">I. Buckland</a>, <a href="/search/physics?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/physics?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/physics?searchtype=author&query=Fujii%2C+T">T. Fujii</a> , et al. (127 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2205.05115v2-abstract-short" style="display: inline;"> In this paper, we present the first high-speed video observation of a cloud-to-ground lightning flash and its associated downward-directed Terrestrial Gamma-ray Flash (TGF). The optical emission of the event was observed by a high-speed video camera running at 40,000 frames per second in conjunction with the Telescope Array Surface Detector, Lightning Mapping Array, interferometer, electric-field… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.05115v2-abstract-full').style.display = 'inline'; document.getElementById('2205.05115v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2205.05115v2-abstract-full" style="display: none;"> In this paper, we present the first high-speed video observation of a cloud-to-ground lightning flash and its associated downward-directed Terrestrial Gamma-ray Flash (TGF). The optical emission of the event was observed by a high-speed video camera running at 40,000 frames per second in conjunction with the Telescope Array Surface Detector, Lightning Mapping Array, interferometer, electric-field fast antenna, and the National Lightning Detection Network. The cloud-to-ground flash associated with the observed TGF was formed by a fast downward leader followed by a very intense return stroke peak current of -154 kA. The TGF occurred while the downward leader was below cloud base, and even when it was halfway in its propagation to ground. The suite of gamma-ray and lightning instruments, timing resolution, and source proximity offer us detailed information and therefore a unique look at the TGF phenomena. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2205.05115v2-abstract-full').style.display = 'none'; document.getElementById('2205.05115v2-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 August, 2023; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 10 May, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Geophysical Research Letters, 50, e2023GL102958 (2023) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2204.11669">arXiv:2204.11669</a> <span> [<a href="https://arxiv.org/pdf/2204.11669">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Image and Video Processing">eess.IV</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Artificial Intelligence">cs.AI</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Medical Physics">physics.med-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/s41746-023-00859-y">10.1038/s41746-023-00859-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Deep-learning-enabled Brain Hemodynamic Mapping Using Resting-state fMRI </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Hou%2C+X">Xirui Hou</a>, <a href="/search/physics?searchtype=author&query=Guo%2C+P">Pengfei Guo</a>, <a href="/search/physics?searchtype=author&query=Wang%2C+P">Puyang Wang</a>, <a href="/search/physics?searchtype=author&query=Liu%2C+P">Peiying Liu</a>, <a href="/search/physics?searchtype=author&query=Lin%2C+D+D+M">Doris D. M. Lin</a>, <a href="/search/physics?searchtype=author&query=Fan%2C+H">Hongli Fan</a>, <a href="/search/physics?searchtype=author&query=Li%2C+Y">Yang Li</a>, <a href="/search/physics?searchtype=author&query=Wei%2C+Z">Zhiliang Wei</a>, <a href="/search/physics?searchtype=author&query=Lin%2C+Z">Zixuan Lin</a>, <a href="/search/physics?searchtype=author&query=Jiang%2C+D">Dengrong Jiang</a>, <a href="/search/physics?searchtype=author&query=Jin%2C+J">Jin Jin</a>, <a href="/search/physics?searchtype=author&query=Kelly%2C+C">Catherine Kelly</a>, <a href="/search/physics?searchtype=author&query=Pillai%2C+J+J">Jay J. Pillai</a>, <a href="/search/physics?searchtype=author&query=Huang%2C+J">Judy Huang</a>, <a href="/search/physics?searchtype=author&query=Pinho%2C+M+C">Marco C. Pinho</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+P">Binu P. Thomas</a>, <a href="/search/physics?searchtype=author&query=Welch%2C+B+G">Babu G. Welch</a>, <a href="/search/physics?searchtype=author&query=Park%2C+D+C">Denise C. Park</a>, <a href="/search/physics?searchtype=author&query=Patel%2C+V+M">Vishal M. Patel</a>, <a href="/search/physics?searchtype=author&query=Hillis%2C+A+E">Argye E. Hillis</a>, <a href="/search/physics?searchtype=author&query=Lu%2C+H">Hanzhang Lu</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="2204.11669v1-abstract-short" style="display: inline;"> Cerebrovascular disease is a leading cause of death globally. Prevention and early intervention are known to be the most effective forms of its management. Non-invasive imaging methods hold great promises for early stratification, but at present lack the sensitivity for personalized prognosis. Resting-state functional magnetic resonance imaging (rs-fMRI), a powerful tool previously used for mappin… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.11669v1-abstract-full').style.display = 'inline'; document.getElementById('2204.11669v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2204.11669v1-abstract-full" style="display: none;"> Cerebrovascular disease is a leading cause of death globally. Prevention and early intervention are known to be the most effective forms of its management. Non-invasive imaging methods hold great promises for early stratification, but at present lack the sensitivity for personalized prognosis. Resting-state functional magnetic resonance imaging (rs-fMRI), a powerful tool previously used for mapping neural activity, is available in most hospitals. Here we show that rs-fMRI can be used to map cerebral hemodynamic function and delineate impairment. By exploiting time variations in breathing pattern during rs-fMRI, deep learning enables reproducible mapping of cerebrovascular reactivity (CVR) and bolus arrive time (BAT) of the human brain using resting-state CO2 fluctuations as a natural 'contrast media'. The deep-learning network was trained with CVR and BAT maps obtained with a reference method of CO2-inhalation MRI, which included data from young and older healthy subjects and patients with Moyamoya disease and brain tumors. We demonstrate the performance of deep-learning cerebrovascular mapping in the detection of vascular abnormalities, evaluation of revascularization effects, and vascular alterations in normal aging. In addition, cerebrovascular maps obtained with the proposed method exhibited excellent reproducibility in both healthy volunteers and stroke patients. Deep-learning resting-state vascular imaging has the potential to become a useful tool in clinical cerebrovascular imaging. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2204.11669v1-abstract-full').style.display = 'none'; document.getElementById('2204.11669v1-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 April, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> npj Digital Medicine (2023) 116 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2203.05090">arXiv:2203.05090</a> <span> [<a href="https://arxiv.org/pdf/2203.05090">pdf</a>, <a href="https://arxiv.org/format/2203.05090">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Cosmology and Nongalactic Astrophysics">astro-ph.CO</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="High Energy Physics - Phenomenology">hep-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Instrumentation and Detectors">physics.ins-det</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/10.1088/1361-6471/ac865e">10.1088/1361-6471/ac865e <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The Forward Physics Facility at the High-Luminosity LHC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Feng%2C+J+L">Jonathan L. Feng</a>, <a href="/search/physics?searchtype=author&query=Kling%2C+F">Felix Kling</a>, <a href="/search/physics?searchtype=author&query=Reno%2C+M+H">Mary Hall Reno</a>, <a href="/search/physics?searchtype=author&query=Rojo%2C+J">Juan Rojo</a>, <a href="/search/physics?searchtype=author&query=Soldin%2C+D">Dennis Soldin</a>, <a href="/search/physics?searchtype=author&query=Anchordoqui%2C+L+A">Luis A. Anchordoqui</a>, <a href="/search/physics?searchtype=author&query=Boyd%2C+J">Jamie Boyd</a>, <a href="/search/physics?searchtype=author&query=Ismail%2C+A">Ahmed Ismail</a>, <a href="/search/physics?searchtype=author&query=Harland-Lang%2C+L">Lucian Harland-Lang</a>, <a href="/search/physics?searchtype=author&query=Kelly%2C+K+J">Kevin J. Kelly</a>, <a href="/search/physics?searchtype=author&query=Pandey%2C+V">Vishvas Pandey</a>, <a href="/search/physics?searchtype=author&query=Trojanowski%2C+S">Sebastian Trojanowski</a>, <a href="/search/physics?searchtype=author&query=Tsai%2C+Y">Yu-Dai Tsai</a>, <a href="/search/physics?searchtype=author&query=Alameddine%2C+J">Jean-Marco Alameddine</a>, <a href="/search/physics?searchtype=author&query=Araki%2C+T">Takeshi Araki</a>, <a href="/search/physics?searchtype=author&query=Ariga%2C+A">Akitaka Ariga</a>, <a href="/search/physics?searchtype=author&query=Ariga%2C+T">Tomoko Ariga</a>, <a href="/search/physics?searchtype=author&query=Asai%2C+K">Kento Asai</a>, <a href="/search/physics?searchtype=author&query=Bacchetta%2C+A">Alessandro Bacchetta</a>, <a href="/search/physics?searchtype=author&query=Balazs%2C+K">Kincso Balazs</a>, <a href="/search/physics?searchtype=author&query=Barr%2C+A+J">Alan J. Barr</a>, <a href="/search/physics?searchtype=author&query=Battistin%2C+M">Michele Battistin</a>, <a href="/search/physics?searchtype=author&query=Bian%2C+J">Jianming Bian</a>, <a href="/search/physics?searchtype=author&query=Bertone%2C+C">Caterina Bertone</a>, <a href="/search/physics?searchtype=author&query=Bai%2C+W">Weidong Bai</a> , et al. (211 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="2203.05090v1-abstract-short" style="display: inline;"> High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe Standard Mod… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.05090v1-abstract-full').style.display = 'inline'; document.getElementById('2203.05090v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2203.05090v1-abstract-full" style="display: none;"> High energy collisions at the High-Luminosity Large Hadron Collider (LHC) produce a large number of particles along the beam collision axis, outside of the acceptance of existing LHC experiments. The proposed Forward Physics Facility (FPF), to be located several hundred meters from the ATLAS interaction point and shielded by concrete and rock, will host a suite of experiments to probe Standard Model (SM) processes and search for physics beyond the Standard Model (BSM). In this report, we review the status of the civil engineering plans and the experiments to explore the diverse physics signals that can be uniquely probed in the forward region. FPF experiments will be sensitive to a broad range of BSM physics through searches for new particle scattering or decay signatures and deviations from SM expectations in high statistics analyses with TeV neutrinos in this low-background environment. High statistics neutrino detection will also provide valuable data for fundamental topics in perturbative and non-perturbative QCD and in weak interactions. Experiments at the FPF will enable synergies between forward particle production at the LHC and astroparticle physics to be exploited. We report here on these physics topics, on infrastructure, detector, and simulation studies, and on future directions to realize the FPF's physics potential. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2203.05090v1-abstract-full').style.display = 'none'; document.getElementById('2203.05090v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">429 pages, contribution to Snowmass 2021</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> UCI-TR-2022-01, CERN-PBC-Notes-2022-001, FERMILAB-PUB-22-094-ND-SCD-T, INT-PUB-22-006, BONN-TH-2022-04 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2202.04825">arXiv:2202.04825</a> <span> [<a href="https://arxiv.org/pdf/2202.04825">pdf</a>, <a href="https://arxiv.org/format/2202.04825">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-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/s41561-021-00886-y">10.1038/s41561-021-00886-y <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A nitrogen-rich atmosphere on ancient Mars consistent with isotopic evolution models </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Hu%2C+R">Renyu Hu</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+T+B">Trent B. Thomas</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="2202.04825v1-abstract-short" style="display: inline;"> The ratio of nitrogen isotopes in the Martian atmosphere is a key constraint on the planet's atmospheric evolution. However, enrichment of the heavy isotope expected due to atmospheric loss from sputtering and photochemical processes is greater than measurements. A massive, multi-bar early CO2-dominated atmosphere and recent volcanic outgassing have been proposed to explain this discrepancy, and m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.04825v1-abstract-full').style.display = 'inline'; document.getElementById('2202.04825v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2202.04825v1-abstract-full" style="display: none;"> The ratio of nitrogen isotopes in the Martian atmosphere is a key constraint on the planet's atmospheric evolution. However, enrichment of the heavy isotope expected due to atmospheric loss from sputtering and photochemical processes is greater than measurements. A massive, multi-bar early CO2-dominated atmosphere and recent volcanic outgassing have been proposed to explain this discrepancy, and many previous models have assumed atmospheric nitrogen rapidly reached a steady state where loss to space balanced volcanic outgassing. Here we show using time-dependent models that the abundance and isotopic composition of nitrogen in the Martian atmosphere can be explained by a family of evolutionary scenarios in which the initial partial pressure of nitrogen is sufficiently high that a steady state is not reached and nitrogen levels gradually decline to present-day values over 4 billion years. Our solutions do not require a multi-bar early CO2 atmosphere and are consistent with volcanic outgassing indicated by both geologic mapping and the atmospheric 36Ar/38Ar ratio. Monte Carlo simulations that include these scenarios estimate that the partial pressure of N2 was 60 - 740 mbar (90% confidence, with a median value of 310 mbar) at 3.8 billion years ago when the valley networks formed. We suggest that such a high nitrogen partial pressure could have contributed substantially to warming on early Mars. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2202.04825v1-abstract-full').style.display = 'none'; document.getElementById('2202.04825v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2022. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Nature Geoscience, published online on February 10, 2022, https://www.nature.com/articles/s41561-021-00886-y</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2201.12621">arXiv:2201.12621</a> <span> [<a href="https://arxiv.org/pdf/2201.12621">pdf</a>, <a href="https://arxiv.org/format/2201.12621">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 Detectors">physics.ins-det</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/10.1016/j.nima.2022.166382">10.1016/j.nima.2022.166382 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Simultaneous scintillation light and charge readout of a pure argon filled Spherical Proportional Counter </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Bouet%2C+R">R. Bouet</a>, <a href="/search/physics?searchtype=author&query=Busto%2C+J">J. Busto</a>, <a href="/search/physics?searchtype=author&query=Cecchini%2C+V">V. Cecchini</a>, <a href="/search/physics?searchtype=author&query=Cerna%2C+C">C. Cerna</a>, <a href="/search/physics?searchtype=author&query=Dastgheibi-Fard%2C+A">A. Dastgheibi-Fard</a>, <a href="/search/physics?searchtype=author&query=Druillole%2C+F">F. Druillole</a>, <a href="/search/physics?searchtype=author&query=Jollet%2C+C">C. Jollet</a>, <a href="/search/physics?searchtype=author&query=Hellmuth%2C+P">P. Hellmuth</a>, <a href="/search/physics?searchtype=author&query=Katsioulas%2C+I">I. Katsioulas</a>, <a href="/search/physics?searchtype=author&query=Knights%2C+P">P. Knights</a>, <a href="/search/physics?searchtype=author&query=Giomataris%2C+I">I. Giomataris</a>, <a href="/search/physics?searchtype=author&query=Gros%2C+M">M. Gros</a>, <a href="/search/physics?searchtype=author&query=Lautridou%2C+P">P. Lautridou</a>, <a href="/search/physics?searchtype=author&query=Meregaglia%2C+A">A. Meregaglia</a>, <a href="/search/physics?searchtype=author&query=Navick%2C+X+F">X. F. Navick</a>, <a href="/search/physics?searchtype=author&query=Neep%2C+T">T. Neep</a>, <a href="/search/physics?searchtype=author&query=Nikolopoulos%2C+K">K. Nikolopoulos</a>, <a href="/search/physics?searchtype=author&query=Perrot%2C+F">F. Perrot</a>, <a href="/search/physics?searchtype=author&query=Piquemal%2C+F">F. Piquemal</a>, <a href="/search/physics?searchtype=author&query=Roche%2C+M">M. Roche</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Ward%2C+R">R. Ward</a>, <a href="/search/physics?searchtype=author&query=Zampaolo%2C+M">M. Zampaolo</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="2201.12621v1-abstract-short" style="display: inline;"> The possible use of a Spherical Proportional Counter for the search of neutrinoless double beta decay is investigated in the R2D2 R&D project. Dual charge and scintillation light readout may improve the detector performance. Tests were carried out with pure argon at 1.1 bar using a 6x6 mm2 silicon photomultiplier. Scintillation light was used for the first time to trigger in a spherical proportion… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.12621v1-abstract-full').style.display = 'inline'; document.getElementById('2201.12621v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2201.12621v1-abstract-full" style="display: none;"> The possible use of a Spherical Proportional Counter for the search of neutrinoless double beta decay is investigated in the R2D2 R&D project. Dual charge and scintillation light readout may improve the detector performance. Tests were carried out with pure argon at 1.1 bar using a 6x6 mm2 silicon photomultiplier. Scintillation light was used for the first time to trigger in a spherical proportional counter. The measured drift time is in excellent agreement with the expectations from simulations. Furthermore the light signal emitted during the avalanche development exhibits features that could be exploited for event characterisation. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2201.12621v1-abstract-full').style.display = 'none'; document.getElementById('2201.12621v1-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, 2022; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> January 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">17 pages,14 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/2111.09962">arXiv:2111.09962</a> <span> [<a href="https://arxiv.org/pdf/2111.09962">pdf</a>, <a href="https://arxiv.org/format/2111.09962">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-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/10.1103/PhysRevD.105.062002">10.1103/PhysRevD.105.062002 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observation of Variations in Cosmic Ray Single Count Rates During Thunderstorms and Implications for Large-Scale Electric Field Changes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/physics?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/physics?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/physics?searchtype=author&query=Arai%2C+Y">Y. Arai</a>, <a href="/search/physics?searchtype=author&query=Arimura%2C+R">R. Arimura</a>, <a href="/search/physics?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/physics?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/physics?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/physics?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/physics?searchtype=author&query=Buckland%2C+I">I. Buckland</a>, <a href="/search/physics?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/physics?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/physics?searchtype=author&query=Chiba%2C+J">J. Chiba</a>, <a href="/search/physics?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/physics?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/physics?searchtype=author&query=Fujisue%2C+K">K. Fujisue</a>, <a href="/search/physics?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/physics?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/physics?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/physics?searchtype=author&query=Fukushima%2C+R">R. Fukushima</a>, <a href="/search/physics?searchtype=author&query=Furlich%2C+G">G. Furlich</a>, <a href="/search/physics?searchtype=author&query=Globus%2C+N">N. Globus</a>, <a href="/search/physics?searchtype=author&query=Gonzalez%2C+R">R. Gonzalez</a>, <a href="/search/physics?searchtype=author&query=Hanlon%2C+W">W. Hanlon</a>, <a href="/search/physics?searchtype=author&query=Hayashi%2C+M">M. Hayashi</a> , et al. (140 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="2111.09962v1-abstract-short" style="display: inline;"> We present the first observation by the Telescope Array Surface Detector (TASD) of the effect of thunderstorms on the development of cosmic ray single count rate intensity over a 700 km$^{2}$ area. Observations of variations in the secondary low-energy cosmic ray counting rate, using the TASD, allow us to study the electric field inside thunderstorms, on a large scale, as it progresses on top of t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09962v1-abstract-full').style.display = 'inline'; document.getElementById('2111.09962v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2111.09962v1-abstract-full" style="display: none;"> We present the first observation by the Telescope Array Surface Detector (TASD) of the effect of thunderstorms on the development of cosmic ray single count rate intensity over a 700 km$^{2}$ area. Observations of variations in the secondary low-energy cosmic ray counting rate, using the TASD, allow us to study the electric field inside thunderstorms, on a large scale, as it progresses on top of the 700 km$^{2}$ detector, without dealing with the limitation of narrow exposure in time and space using balloons and aircraft detectors. In this work, variations in the cosmic ray intensity (single count rate) using the TASD, were studied and found to be on average at the $\sim(0.5-1)\%$ and up to 2\% level. These observations were found to be both in excess and in deficit. They were also found to be correlated with lightning in addition to thunderstorms. These variations lasted for tens of minutes; their footprint on the ground ranged from 6 to 24 km in diameter and moved in the same direction as the thunderstorm. With the use of simple electric field models inside the cloud and between cloud to ground, the observed variations in the cosmic ray single count rate were recreated using CORSIKA simulations. Depending on the electric field model used and the direction of the electric field in that model, the electric field magnitude that reproduces the observed low-energy cosmic ray single count rate variations was found to be approximately between 0.2-0.4 GV. This in turn allows us to get a reasonable insight on the electric field and its effect on cosmic ray air showers inside thunderstorms. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2111.09962v1-abstract-full').style.display = 'none'; document.getElementById('2111.09962v1-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 November, 2021; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 2021. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2103.01086">arXiv:2103.01086</a> <span> [<a href="https://arxiv.org/pdf/2103.01086">pdf</a>, <a href="https://arxiv.org/ps/2103.01086">ps</a>, <a href="https://arxiv.org/format/2103.01086">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="Instrumentation and Detectors">physics.ins-det</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/10.1016/j.nima.2021.165726">10.1016/j.nima.2021.165726 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Surface detectors of the TAx4 experiment </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Telescope+Array+Collaboration"> Telescope Array Collaboration</a>, <a href="/search/physics?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/physics?searchtype=author&query=Abe%2C+M">M. Abe</a>, <a href="/search/physics?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/physics?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/physics?searchtype=author&query=Arai%2C+Y">Y. Arai</a>, <a href="/search/physics?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/physics?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/physics?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/physics?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/physics?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/physics?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/physics?searchtype=author&query=Chiba%2C+J">J. Chiba</a>, <a href="/search/physics?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/physics?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/physics?searchtype=author&query=Fujisue%2C+K">K. Fujisue</a>, <a href="/search/physics?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/physics?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/physics?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/physics?searchtype=author&query=Fukushima%2C+R">R. Fukushima</a>, <a href="/search/physics?searchtype=author&query=Furlich%2C+G">G. Furlich</a>, <a href="/search/physics?searchtype=author&query=Hanlon%2C+W">W. Hanlon</a>, <a href="/search/physics?searchtype=author&query=Hayashi%2C+M">M. Hayashi</a>, <a href="/search/physics?searchtype=author&query=Hayashida%2C+N">N. Hayashida</a>, <a href="/search/physics?searchtype=author&query=Hibino%2C+K">K. Hibino</a> , et al. (124 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="2103.01086v1-abstract-short" style="display: inline;"> Telescope Array (TA) is the largest ultrahigh energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. It explores the origin of UHECRs by measuring their energy spectrum, arrival-direction distribution, and mass composition using a surface detector (SD) array covering approximately 700 km$^2$ and fluorescence detector (FD) stations. TA has found evidence for a cluster of cosmic rays with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01086v1-abstract-full').style.display = 'inline'; document.getElementById('2103.01086v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2103.01086v1-abstract-full" style="display: none;"> Telescope Array (TA) is the largest ultrahigh energy cosmic-ray (UHECR) observatory in the Northern Hemisphere. It explores the origin of UHECRs by measuring their energy spectrum, arrival-direction distribution, and mass composition using a surface detector (SD) array covering approximately 700 km$^2$ and fluorescence detector (FD) stations. TA has found evidence for a cluster of cosmic rays with energies greater than 57 EeV. In order to confirm this evidence with more data, it is necessary to increase the data collection rate.We have begun building an expansion of TA that we call TAx4. In this paper, we explain the motivation, design, technical features, and expected performance of the TAx4 SD. We also present TAx4's current status and examples of the data that have already been collected. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2103.01086v1-abstract-full').style.display = 'none'; document.getElementById('2103.01086v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 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">26 pages, 17 figures, submitted to Nuclear Inst. and Methods in Physics Research, A</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.14327">arXiv:2009.14327</a> <span> [<a href="https://arxiv.org/pdf/2009.14327">pdf</a>, <a href="https://arxiv.org/format/2009.14327">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</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="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2019JD031940">10.1029/2019JD031940 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Observations of the Origin of Downward Terrestrial Gamma-Ray Flashes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/physics?searchtype=author&query=Krehbiel%2C+P+R">P. R. Krehbiel</a>, <a href="/search/physics?searchtype=author&query=Remington%2C+J">J. Remington</a>, <a href="/search/physics?searchtype=author&query=Stanley%2C+M+A">M. A. Stanley</a>, <a href="/search/physics?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/physics?searchtype=author&query=LeVon%2C+R">R. LeVon</a>, <a href="/search/physics?searchtype=author&query=Rison%2C+W">W. Rison</a>, <a href="/search/physics?searchtype=author&query=Rodeheffer%2C+D">D. Rodeheffer</a>, <a href="/search/physics?searchtype=author&query=Collaboration%2C+t+T+A+S">the Telescope Array Scientific Collaboration</a>, <a href="/search/physics?searchtype=author&query=%3A"> :</a>, <a href="/search/physics?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/physics?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/physics?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/physics?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/physics?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/physics?searchtype=author&query=Byrne%2C+M">M. Byrne</a>, <a href="/search/physics?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/physics?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/physics?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/physics?searchtype=author&query=di+Matteo%2C+A">A. di Matteo</a>, <a href="/search/physics?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/physics?searchtype=author&query=Fujita%2C+K">K. Fujita</a>, <a href="/search/physics?searchtype=author&query=Fujiwara%2C+R">R. Fujiwara</a>, <a href="/search/physics?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/physics?searchtype=author&query=Furlich%2C+G">G. Furlich</a> , et al. (116 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.14327v2-abstract-short" style="display: inline;"> In this paper we report the first close, high-resolution observations of downward-directed terrestrial gamma-ray flashes (TGFs) detected by the large-area Telescope Array cosmic ray observatory, obtained in conjunction with broadband VHF interferometer and fast electric field change measurements of the parent discharge. The results show that the TGFs occur during strong initial breakdown pulses (I… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14327v2-abstract-full').style.display = 'inline'; document.getElementById('2009.14327v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.14327v2-abstract-full" style="display: none;"> In this paper we report the first close, high-resolution observations of downward-directed terrestrial gamma-ray flashes (TGFs) detected by the large-area Telescope Array cosmic ray observatory, obtained in conjunction with broadband VHF interferometer and fast electric field change measurements of the parent discharge. The results show that the TGFs occur during strong initial breakdown pulses (IBPs) in the first few milliseconds of negative cloud-to-ground and low-altitude intracloud flashes, and that the IBPs are produced by a newly-identified streamer-based discharge process called fast negative breakdown. The observations indicate the relativistic runaway electron avalanches (RREAs) responsible for producing the TGFs are initiated by embedded spark-like transient conducting events (TCEs) within the fast streamer system, and potentially also by individual fast streamers themselves. The TCEs are inferred to be the cause of impulsive sub-pulses that are characteristic features of classic IBP sferics. Additional development of the avalanches would be facilitated by the enhanced electric field ahead of the advancing front of the fast negative breakdown. In addition to showing the nature of IBPs and their enigmatic sub-pulses, the observations also provide a possible explanation for the unsolved question of how the streamer to leader transition occurs during the initial negative breakdown, namely as a result of strong currents flowing in the final stage of successive IBPs, extending backward through both the IBP itself and the negative streamer breakdown preceding the IBP. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14327v2-abstract-full').style.display = 'none'; document.getElementById('2009.14327v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 12 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Typo fixed and reference added. Manuscript is 36 pages. Supplemental Information is 42 pages. This paper is to be published in the Journal of Geophysical Research: Atmospheres. Online data repository: Open Science Framework DOI: 10.17605/OSF.IO/Z3XDA</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.14078">arXiv:2009.14078</a> <span> [<a href="https://arxiv.org/pdf/2009.14078">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-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/10.1093/mnras/staa3364">10.1093/mnras/staa3364 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma Ray Bursts: Not so Much Deadlier than We Thought </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Atri%2C+D">Dimitra Atri</a>, <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</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="2009.14078v2-abstract-short" style="display: inline;"> We analyze the additional effect on planetary atmospheres of recently detected gamma-ray burst afterglow photons in the range up to 1 TeV. For an Earth-like atmosphere we find that there is a small additional depletion in ozone versus that modeled for only prompt emission. We also find a small enhancement of muon flux at the planet surface. Overall, we conclude that the additional afterglow emissi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14078v2-abstract-full').style.display = 'inline'; document.getElementById('2009.14078v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.14078v2-abstract-full" style="display: none;"> We analyze the additional effect on planetary atmospheres of recently detected gamma-ray burst afterglow photons in the range up to 1 TeV. For an Earth-like atmosphere we find that there is a small additional depletion in ozone versus that modeled for only prompt emission. We also find a small enhancement of muon flux at the planet surface. Overall, we conclude that the additional afterglow emission, even with TeV photons, does not result in a significantly larger impact over that found in past studies. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.14078v2-abstract-full').style.display = 'none'; document.getElementById('2009.14078v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 October, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 29 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">Replaced with version to be published in MNRAS</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> MNRAS 500, 1970-1973 (2021) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2009.01693">arXiv:2009.01693</a> <span> [<a href="https://arxiv.org/pdf/2009.01693">pdf</a>, <a href="https://arxiv.org/format/2009.01693">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 Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Experiment">hep-ex</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Physics - Phenomenology">hep-ph</span> </div> </div> <p class="title is-5 mathjax"> An Update to the Letter of Intent for MATHUSLA: Search for Long-Lived Particles at the HL-LHC </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Alpigiani%2C+C">Cristiano Alpigiani</a>, <a href="/search/physics?searchtype=author&query=Arteaga-Vel%C3%A1zquez%2C+J+C">Juan Carlos Arteaga-Vel谩zquez</a>, <a href="/search/physics?searchtype=author&query=Ball%2C+A">Austin Ball</a>, <a href="/search/physics?searchtype=author&query=Barak%2C+L">Liron Barak</a>, <a href="/search/physics?searchtype=author&query=Barron%2C+J">Jared Barron</a>, <a href="/search/physics?searchtype=author&query=Batell%2C+B">Brian Batell</a>, <a href="/search/physics?searchtype=author&query=Beacham%2C+J">James Beacham</a>, <a href="/search/physics?searchtype=author&query=Benhammo%2C+Y">Yan Benhammo</a>, <a href="/search/physics?searchtype=author&query=Caballero-Mora%2C+K+S">Karen Salom茅 Caballero-Mora</a>, <a href="/search/physics?searchtype=author&query=Camarri%2C+P">Paolo Camarri</a>, <a href="/search/physics?searchtype=author&query=Cardarelli%2C+R">Roberto Cardarelli</a>, <a href="/search/physics?searchtype=author&query=Chou%2C+J+P">John Paul Chou</a>, <a href="/search/physics?searchtype=author&query=Cui%2C+W">Wentao Cui</a>, <a href="/search/physics?searchtype=author&query=Curtin%2C+D">David Curtin</a>, <a href="/search/physics?searchtype=author&query=Diamond%2C+M">Miriam Diamond</a>, <a href="/search/physics?searchtype=author&query=Dienes%2C+K+R">Keith R. Dienes</a>, <a href="/search/physics?searchtype=author&query=Dougherty%2C+L+A">Liam Andrew Dougherty</a>, <a href="/search/physics?searchtype=author&query=Di+Sciascio%2C+G">Giuseppe Di Sciascio</a>, <a href="/search/physics?searchtype=author&query=Drewes%2C+M">Marco Drewes</a>, <a href="/search/physics?searchtype=author&query=Etzion%2C+E">Erez Etzion</a>, <a href="/search/physics?searchtype=author&query=Essig%2C+R">Rouven Essig</a>, <a href="/search/physics?searchtype=author&query=Evans%2C+J">Jared Evans</a>, <a href="/search/physics?searchtype=author&query=T%C3%A9llez%2C+A+F">Arturo Fern谩ndez T茅llez</a>, <a href="/search/physics?searchtype=author&query=Fischer%2C+O">Oliver Fischer</a>, <a href="/search/physics?searchtype=author&query=Freeman%2C+J">Jim Freeman</a> , et al. (58 additional authors not shown) </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="2009.01693v1-abstract-short" style="display: inline;"> We report on recent progress in the design of the proposed MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC, updating the information in the original Letter of Intent (LoI), see CDS:LHCC-I-031, arXiv:1811.00927. A suitable site has been identified at LHC Point 5 that is closer to the CMS Interaction Point (IP) than assumed in the LoI. The decay volume has been increased from 20 m to 25 m… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.01693v1-abstract-full').style.display = 'inline'; document.getElementById('2009.01693v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2009.01693v1-abstract-full" style="display: none;"> We report on recent progress in the design of the proposed MATHUSLA Long Lived Particle (LLP) detector for the HL-LHC, updating the information in the original Letter of Intent (LoI), see CDS:LHCC-I-031, arXiv:1811.00927. A suitable site has been identified at LHC Point 5 that is closer to the CMS Interaction Point (IP) than assumed in the LoI. The decay volume has been increased from 20 m to 25 m in height. Engineering studies have been made in order to locate much of the decay volume below ground, bringing the detector even closer to the IP. With these changes, a 100 m x 100 m detector has the same physics reach for large c$蟿$ as the 200 m x 200 m detector described in the LoI and other studies. The performance for small c$蟿$ is improved because of the proximity to the IP. Detector technology has also evolved while retaining the strip-like sensor geometry in Resistive Plate Chambers (RPC) described in the LoI. The present design uses extruded scintillator bars read out using wavelength shifting fibers and silicon photomultipliers (SiPM). Operations will be simpler and more robust with much lower operating voltages and without the use of greenhouse gases. Manufacturing is straightforward and should result in cost savings. Understanding of backgrounds has also significantly advanced, thanks to new simulation studies and measurements taken at the MATHUSLA test stand operating above ATLAS in 2018. We discuss next steps for the MATHUSLA collaboration, and identify areas where new members can make particularly important contributions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2009.01693v1-abstract-full').style.display = 'none'; document.getElementById('2009.01693v1-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 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> September 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">22 pages + references, 12 Figures</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Report number:</span> CERN-LHCC-2020-014, LHCC-I-031-ADD-1 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.02570">arXiv:2007.02570</a> <span> [<a href="https://arxiv.org/pdf/2007.02570">pdf</a>, <a href="https://arxiv.org/format/2007.02570">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 Detectors">physics.ins-det</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/10.1088/1748-0221/16/03/P03012">10.1088/1748-0221/16/03/P03012 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> R2D2 spherical TPC: first energy resolution results </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Bouet%2C+R">R. Bouet</a>, <a href="/search/physics?searchtype=author&query=Busto%2C+J">J. Busto</a>, <a href="/search/physics?searchtype=author&query=Cecchini%2C+V">V. Cecchini</a>, <a href="/search/physics?searchtype=author&query=Cerna%2C+C">C. Cerna</a>, <a href="/search/physics?searchtype=author&query=Dastgheibi-Fard%2C+A">A. Dastgheibi-Fard</a>, <a href="/search/physics?searchtype=author&query=Druillole%2C+F">F. Druillole</a>, <a href="/search/physics?searchtype=author&query=Jollet%2C+C">C. Jollet</a>, <a href="/search/physics?searchtype=author&query=Hellmuth%2C+P">P. Hellmuth</a>, <a href="/search/physics?searchtype=author&query=Katsioulas%2C+I">I. Katsioulas</a>, <a href="/search/physics?searchtype=author&query=Knights%2C+P">P. Knights</a>, <a href="/search/physics?searchtype=author&query=Giomataris%2C+I">I. Giomataris</a>, <a href="/search/physics?searchtype=author&query=Gros%2C+M">M. Gros</a>, <a href="/search/physics?searchtype=author&query=Lautridou%2C+P">P. Lautridou</a>, <a href="/search/physics?searchtype=author&query=Meregaglia%2C+A">A. Meregaglia</a>, <a href="/search/physics?searchtype=author&query=Navick%2C+X+F">X. F. Navick</a>, <a href="/search/physics?searchtype=author&query=Neep%2C+T">T. Neep</a>, <a href="/search/physics?searchtype=author&query=Nikolopoulos%2C+K">K. Nikolopoulos</a>, <a href="/search/physics?searchtype=author&query=Perrot%2C+F">F. Perrot</a>, <a href="/search/physics?searchtype=author&query=Piquemal%2C+F">F. Piquemal</a>, <a href="/search/physics?searchtype=author&query=Roche%2C+M">M. Roche</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Ward%2C+R">R. Ward</a>, <a href="/search/physics?searchtype=author&query=Zampaolo%2C+M">M. Zampaolo</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="2007.02570v2-abstract-short" style="display: inline;"> Spherical time projection chambers (TPC), also known as spherical proportional counters, are employed in the search for rare phenomena, such as light Dark Matter candidates. The spherical TPC exhibits a number of essential features, making it a promising candidate for the search of neutrinoless double beta decay ($尾\beta0谓$). A tonne-scale spherical TPC experiment could cover a region of parameter… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.02570v2-abstract-full').style.display = 'inline'; document.getElementById('2007.02570v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.02570v2-abstract-full" style="display: none;"> Spherical time projection chambers (TPC), also known as spherical proportional counters, are employed in the search for rare phenomena, such as light Dark Matter candidates. The spherical TPC exhibits a number of essential features, making it a promising candidate for the search of neutrinoless double beta decay ($尾\beta0谓$). A tonne-scale spherical TPC experiment could cover a region of parameter space relevant for the inverted mass hierarchy with a few years of data taking. In this direction, the major R\&D goal of the R2D2 effort is the demonstration of the required energy resolution. First results from an argon-filled prototype detector are reported, demonstrating an energy resolution of 1.1\% FWHM for 5.3~MeV $伪$ tracks in the 0.2 to 1.1~bar pressure range. This is a major milestone in terms of energy resolution, paving the way for further studies with xenon gas, and the possible use of this technology for $尾\beta0谓$ searches. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.02570v2-abstract-full').style.display = 'none'; document.getElementById('2007.02570v2-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, 2021; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 2020. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2007.01887">arXiv:2007.01887</a> <span> [<a href="https://arxiv.org/pdf/2007.01887">pdf</a>, <a href="https://arxiv.org/ps/2007.01887">ps</a>, <a href="https://arxiv.org/format/2007.01887">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Geophysics">physics.geo-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/10.1073/pnas.2013774117">10.1073/pnas.2013774117 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Supernova Triggers for End-Devonian Extinctions </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Fields%2C+B+D">Brian D. Fields</a>, <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</a>, <a href="/search/physics?searchtype=author&query=Ellis%2C+J">John Ellis</a>, <a href="/search/physics?searchtype=author&query=Ertel%2C+A+F">Adrienne F. Ertel</a>, <a href="/search/physics?searchtype=author&query=Fry%2C+B+J">Brian J. Fry</a>, <a href="/search/physics?searchtype=author&query=Lieberman%2C+B+S">Bruce S. Lieberman</a>, <a href="/search/physics?searchtype=author&query=Liu%2C+Z">Zhenghai Liu</a>, <a href="/search/physics?searchtype=author&query=Miller%2C+J+A">Jesse A. Miller</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="2007.01887v2-abstract-short" style="display: inline;"> The Late Devonian was a protracted period of low speciation resulting in biodiversity decline, culminating in extinction events near the Devonian-Carboniferous boundary. Recent evidence indicates that the final extinction event may have coincided with a dramatic drop in stratospheric ozone, possibly due to a global temperature rise. Here we study an alternative possible cause for the postulated oz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.01887v2-abstract-full').style.display = 'inline'; document.getElementById('2007.01887v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2007.01887v2-abstract-full" style="display: none;"> The Late Devonian was a protracted period of low speciation resulting in biodiversity decline, culminating in extinction events near the Devonian-Carboniferous boundary. Recent evidence indicates that the final extinction event may have coincided with a dramatic drop in stratospheric ozone, possibly due to a global temperature rise. Here we study an alternative possible cause for the postulated ozone drop: a nearby supernova explosion that could inflict damage by accelerating cosmic rays that can deliver ionizing radiation for up to $\sim 100$ kyr. We therefore propose that the end-Devonian extinctions were triggered by supernova explosions at $\sim 20$ pc, somewhat beyond the "kill distance" that would have precipitated a full mass extinction. Such nearby supernovae are likely due to core-collapses of massive stars; these are concentrated in the thin Galactic disk where the Sun resides. Detecting either of the long-lived radioisotopes Sm-146 or Pu-244 in one or more end-Devonian extinction strata would confirm a supernova origin, point to the core-collapse explosion of a massive star, and probe supernova nucleosythesis. Other possible tests of the supernova hypothesis are discussed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2007.01887v2-abstract-full').style.display = 'none'; document.getElementById('2007.01887v2-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 August, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 3 July, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">3 pages, no figures. Matches published version. Creative Commons CC BY-NC-ND license</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> PNAS 117, 35, 21008-21010 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2006.15079">arXiv:2006.15079</a> <span> [<a href="https://arxiv.org/pdf/2006.15079">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-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/10.1103/PhysRevResearch.2.043076">10.1103/PhysRevResearch.2.043076 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Ozone depletion-induced climate change following a 50 pc supernova </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Ratterman%2C+C+L">Cody L. Ratterman</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="2006.15079v2-abstract-short" style="display: inline;"> Ozone in Earth's atmosphere is known to have a radiative forcing effect on climate. Motivated by geochemical evidence for one or more nearby supernovae about 2.6 million years ago, we have investigated the question of whether a supernova at about 50 pc could cause a change in Earth's climate through its impact on atmospheric ozone concentrations. We used the "Planet Simulator" (PlaSim) intermediat… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.15079v2-abstract-full').style.display = 'inline'; document.getElementById('2006.15079v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2006.15079v2-abstract-full" style="display: none;"> Ozone in Earth's atmosphere is known to have a radiative forcing effect on climate. Motivated by geochemical evidence for one or more nearby supernovae about 2.6 million years ago, we have investigated the question of whether a supernova at about 50 pc could cause a change in Earth's climate through its impact on atmospheric ozone concentrations. We used the "Planet Simulator" (PlaSim) intermediate-complexity climate model with prescribed ozone profiles taken from existing atmospheric chemistry modeling. We found that the effect on globally averaged surface temperature is small, but localized changes are larger and differences in atmospheric circulation and precipitation patterns could have regional impacts. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2006.15079v2-abstract-full').style.display = 'none'; document.getElementById('2006.15079v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 September, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 26 June, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">Accepted for publication in Physical Review Research (replaced submitted version with accepted version)</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. Research 2, 043076 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/2005.01999">arXiv:2005.01999</a> <span> [<a href="https://arxiv.org/pdf/2005.01999">pdf</a>, <a href="https://arxiv.org/format/2005.01999">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atomic Physics">physics.atom-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/10.1103/PhysRevA.102.042825">10.1103/PhysRevA.102.042825 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Electron capture of Xe$^{54+}$ in collisions with H${_2}$ molecules in the energy range between 5.5 MeV/u and 30.9 MeV/u </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Kr%C3%B6ger%2C+F+M">F. M. Kr枚ger</a>, <a href="/search/physics?searchtype=author&query=Weber%2C+G">G. Weber</a>, <a href="/search/physics?searchtype=author&query=Herdrich%2C+M+O">M. O. Herdrich</a>, <a href="/search/physics?searchtype=author&query=Glorius%2C+J">J. Glorius</a>, <a href="/search/physics?searchtype=author&query=Langer%2C+C">C. Langer</a>, <a href="/search/physics?searchtype=author&query=Slavkovsk%C3%A1%2C+Z">Z. Slavkovsk谩</a>, <a href="/search/physics?searchtype=author&query=Bott%2C+L">L. Bott</a>, <a href="/search/physics?searchtype=author&query=Brandau%2C+C">C. Brandau</a>, <a href="/search/physics?searchtype=author&query=Br%C3%BCckner%2C+B">B. Br眉ckner</a>, <a href="/search/physics?searchtype=author&query=Blaum%2C+K">K. Blaum</a>, <a href="/search/physics?searchtype=author&query=Chen%2C+X">X. Chen</a>, <a href="/search/physics?searchtype=author&query=Dababneh%2C+S">S. Dababneh</a>, <a href="/search/physics?searchtype=author&query=Davinson%2C+T">T. Davinson</a>, <a href="/search/physics?searchtype=author&query=Erbacher%2C+P">P. Erbacher</a>, <a href="/search/physics?searchtype=author&query=Fiebiger%2C+S">S. Fiebiger</a>, <a href="/search/physics?searchtype=author&query=Ga%C3%9Fner%2C+T">T. Ga脽ner</a>, <a href="/search/physics?searchtype=author&query=G%C3%B6bel%2C+K">K. G枚bel</a>, <a href="/search/physics?searchtype=author&query=Groothuis%2C+M">M. Groothuis</a>, <a href="/search/physics?searchtype=author&query=Gumberidze%2C+A">A. Gumberidze</a>, <a href="/search/physics?searchtype=author&query=Gy%C3%BCrky%2C+G">Gy. Gy眉rky</a>, <a href="/search/physics?searchtype=author&query=Hagmann%2C+S">S. Hagmann</a>, <a href="/search/physics?searchtype=author&query=Hahn%2C+C">C. Hahn</a>, <a href="/search/physics?searchtype=author&query=Heil%2C+M">M. Heil</a>, <a href="/search/physics?searchtype=author&query=Hess%2C+R">R. Hess</a>, <a href="/search/physics?searchtype=author&query=Hensch%2C+R">R. Hensch</a> , et al. (41 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="2005.01999v2-abstract-short" style="display: inline;"> The electron capture process was studied for Xe$^{54+}$ colliding with H$_2$ molecules at the internal gas target of the ESR storage ring at GSI, Darmstadt. Cross section values for electron capture into excited projectile states were deduced from the observed emission cross section of Lyman radiation, being emitted by the hydrogen-like ions subsequent to the capture of a target electron. The ion… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.01999v2-abstract-full').style.display = 'inline'; document.getElementById('2005.01999v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="2005.01999v2-abstract-full" style="display: none;"> The electron capture process was studied for Xe$^{54+}$ colliding with H$_2$ molecules at the internal gas target of the ESR storage ring at GSI, Darmstadt. Cross section values for electron capture into excited projectile states were deduced from the observed emission cross section of Lyman radiation, being emitted by the hydrogen-like ions subsequent to the capture of a target electron. The ion beam energy range was varied between 5.5 MeV/u and 30.9 MeV/u by applying the deceleration mode of the ESR. Thus, electron capture data was recorded at the intermediate and in particular the low collision energy regime, well below the beam energy necessary to produce bare xenon ions. The obtained data is found to be in reasonable qualitative agreement with theoretical approaches, while a commonly applied empirical formula significantly overestimates the experimental findings. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('2005.01999v2-abstract-full').style.display = 'none'; document.getElementById('2005.01999v2-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 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 5 May, 2020; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2020. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Phys. Rev. A 102, 042825 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1912.11042">arXiv:1912.11042</a> <span> [<a href="https://arxiv.org/pdf/1912.11042">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 Detectors">physics.ins-det</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</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/10.1016/j.nima.2020.163941">10.1016/j.nima.2020.163941 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> First investigation of the response of solar cells to heavy ions above 1 AMeV </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Henriques%2C+A">A. Henriques</a>, <a href="/search/physics?searchtype=author&query=Jurado%2C+B">B. Jurado</a>, <a href="/search/physics?searchtype=author&query=Pibernat%2C+J">J. Pibernat</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+J+C">J. C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Denis-Petit%2C+D">D. Denis-Petit</a>, <a href="/search/physics?searchtype=author&query=Chiron%2C+T">T. Chiron</a>, <a href="/search/physics?searchtype=author&query=Gaudefroy%2C+L">L. Gaudefroy</a>, <a href="/search/physics?searchtype=author&query=Glorius%2C+J">J. Glorius</a>, <a href="/search/physics?searchtype=author&query=Litvinov%2C+Y+A">Yu. A. Litvinov</a>, <a href="/search/physics?searchtype=author&query=Mathieu%2C+L">L. Mathieu</a>, <a href="/search/physics?searchtype=author&query=M%C3%A9ot%2C+V">V. M茅ot</a>, <a href="/search/physics?searchtype=author&query=P%C3%A9rez-S%C3%A1nchez%2C+R">R. P茅rez-S谩nchez</a>, <a href="/search/physics?searchtype=author&query=Roig%2C+O">O. Roig</a>, <a href="/search/physics?searchtype=author&query=Spillmann%2C+U">U. Spillmann</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+A">B. A. Thomas</a>, <a href="/search/physics?searchtype=author&query=Tsekhanovich%2C+I">I. Tsekhanovich</a>, <a href="/search/physics?searchtype=author&query=Varga%2C+L">L. Varga</a>, <a href="/search/physics?searchtype=author&query=Xing%2C+Y">Y. Xing</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="1912.11042v2-abstract-short" style="display: inline;"> Solar cells have been used since several decades for the detection of fission fragments at about 1 AMeV. The advantages of solar cells regarding their cost (few euros) and radiation damage resistance make them an interesting candidate for heavy ion detection and an appealing alternative to silicon detectors. A first exploratory measurement of the response of solar cells to heavy ions at energies a… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.11042v2-abstract-full').style.display = 'inline'; document.getElementById('1912.11042v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.11042v2-abstract-full" style="display: none;"> Solar cells have been used since several decades for the detection of fission fragments at about 1 AMeV. The advantages of solar cells regarding their cost (few euros) and radiation damage resistance make them an interesting candidate for heavy ion detection and an appealing alternative to silicon detectors. A first exploratory measurement of the response of solar cells to heavy ions at energies above 1 AMeV has been performed at the GANIL facility, Caen, France. Such measurements were performed with 84Kr and 129Xe beams ranging from 7 to 13 AMeV. The energy and time response of several types of solar cells were studied. The best performance was observed for cells of 10x10 mm2, with an energy and time resolution of 蟽(E)/E=1.4% and 3.6 ns (FWHM), respectively. Irradiations at rates from a few hundred to 106 particles per second were also performed to investigate the behavior of the cells with increasing intensity. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.11042v2-abstract-full').style.display = 'none'; document.getElementById('1912.11042v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 April, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 22 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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, 14 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/1912.10841">arXiv:1912.10841</a> <span> [<a href="https://arxiv.org/pdf/1912.10841">pdf</a>, <a href="https://arxiv.org/format/1912.10841">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="Instrumentation and Detectors">physics.ins-det</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/10.1051/0004-6361/201936777">10.1051/0004-6361/201936777 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Wideband 67-116 GHz receiver development for ALMA Band 2 </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Yagoubov%2C+P">P. Yagoubov</a>, <a href="/search/physics?searchtype=author&query=Mroczkowski%2C+T">T. Mroczkowski</a>, <a href="/search/physics?searchtype=author&query=Belitsky%2C+V">V. Belitsky</a>, <a href="/search/physics?searchtype=author&query=Cuadrado-Calle%2C+D">D. Cuadrado-Calle</a>, <a href="/search/physics?searchtype=author&query=Cuttaia%2C+F">F. Cuttaia</a>, <a href="/search/physics?searchtype=author&query=Fuller%2C+G+A">G. A. Fuller</a>, <a href="/search/physics?searchtype=author&query=Gallego%2C+J+-">J. -D. Gallego</a>, <a href="/search/physics?searchtype=author&query=Gonzalez%2C+A">A. Gonzalez</a>, <a href="/search/physics?searchtype=author&query=Kaneko%2C+K">K. Kaneko</a>, <a href="/search/physics?searchtype=author&query=Mena%2C+P">P. Mena</a>, <a href="/search/physics?searchtype=author&query=Molina%2C+R">R. Molina</a>, <a href="/search/physics?searchtype=author&query=Nesti%2C+R">R. Nesti</a>, <a href="/search/physics?searchtype=author&query=Tapia%2C+V">V. Tapia</a>, <a href="/search/physics?searchtype=author&query=Villa%2C+F">F. Villa</a>, <a href="/search/physics?searchtype=author&query=Beltran%2C+M">M. Beltran</a>, <a href="/search/physics?searchtype=author&query=Cavaliere%2C+F">F. Cavaliere</a>, <a href="/search/physics?searchtype=author&query=Ceru%2C+J">J. Ceru</a>, <a href="/search/physics?searchtype=author&query=Chesmore%2C+G+E">G. E. Chesmore</a>, <a href="/search/physics?searchtype=author&query=Coughlin%2C+K">K. Coughlin</a>, <a href="/search/physics?searchtype=author&query=De+Breuck%2C+C">C. De Breuck</a>, <a href="/search/physics?searchtype=author&query=Fredrixon%2C+M">M. Fredrixon</a>, <a href="/search/physics?searchtype=author&query=George%2C+D">D. George</a>, <a href="/search/physics?searchtype=author&query=Gibson%2C+H">H. Gibson</a>, <a href="/search/physics?searchtype=author&query=Golec%2C+J">J. Golec</a>, <a href="/search/physics?searchtype=author&query=Josaitis%2C+A">A. Josaitis</a> , et al. (21 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="1912.10841v3-abstract-short" style="display: inline;"> ALMA has been operating since 2011, but has not yet been populated with the full suite of intended frequency bands. In particular, ALMA Band 2 (67-90 GHz) is the final band in the original ALMA band definition to be approved for production. We aim to produce a wideband, tuneable, sideband-separating receiver with 28 GHz of instantaneous bandwidth per polarisation operating in the sky frequency ran… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.10841v3-abstract-full').style.display = 'inline'; document.getElementById('1912.10841v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1912.10841v3-abstract-full" style="display: none;"> ALMA has been operating since 2011, but has not yet been populated with the full suite of intended frequency bands. In particular, ALMA Band 2 (67-90 GHz) is the final band in the original ALMA band definition to be approved for production. We aim to produce a wideband, tuneable, sideband-separating receiver with 28 GHz of instantaneous bandwidth per polarisation operating in the sky frequency range 67-116 GHz. Our design anticipates new ALMA requirements following the recommendations in the 2030 ALMA Development Roadmap. The cryogenic cartridge is designed to be compatible with the ALMA Band 2 cartridge slot, where the coldest components -- the feedhorns, orthomode transducers, and cryogenic low noise amplifiers -- operate at a temperature of 15 K. We use multiple simulation methods and tools to optimise our designs for both the passive optics and the active components. The cryogenic cartridge interfaces with a room temperature cartridge hosting the local oscillator (LO) and the downconverter module. This warm cartridge is largely based on GaAs semiconductor technology and is optimised to match the cryogenic receiver bandwidth with the required instantaneous LO tuning range. Our collaboration has designed, fabricated, and tested multiple technical solutions for each of the components, producing a state-of-the-art receiver covering the full ALMA Band 2 & 3 atmospheric window. The receiver is suitable for deployment on ALMA in the coming years, and is capable of dual-polarisation, sideband-separating observations in intermediate frequency bands spanning 4-18 GHz, for a total of 28 GHz on-sky bandwidth per polarisation channel. We conclude that the 67-116 GHz wideband implementation for ALMA Band 2 is now feasible, and this receiver is a compelling instrumental upgrade that will enhance observational capabilities and scientific reach. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1912.10841v3-abstract-full').style.display = 'none'; document.getElementById('1912.10841v3-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, 2020; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 20 December, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 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">23 pages, accepted for publication in A&A on 20 Dec 2019. This version corrects the affiliations of 2 co-authors</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> A&A 634, A46 (2020) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.10188">arXiv:1911.10188</a> <span> [<a href="https://arxiv.org/pdf/1911.10188">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Biological Physics">physics.bio-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</span> </div> </div> <p class="title is-5 mathjax"> Biological Impact of Ozone Depletion at the End-Permian: A modeling study </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Oberle%2C+J+M">Jacob M. Oberle</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="1911.10188v1-abstract-short" style="display: inline;"> The end-Permian mass extinction is the most severe known from the fossil record. The most likely cause is massive volcanic activity associated with the formation of the Permo-Triassic Siberian flood basalts. A proposed mechanism for extinction due to this volcanic activity is depletion of stratospheric ozone, leading to increased penetration of biologically damaging Solar ultraviolet-B (UVB) radia… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.10188v1-abstract-full').style.display = 'inline'; document.getElementById('1911.10188v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.10188v1-abstract-full" style="display: none;"> The end-Permian mass extinction is the most severe known from the fossil record. The most likely cause is massive volcanic activity associated with the formation of the Permo-Triassic Siberian flood basalts. A proposed mechanism for extinction due to this volcanic activity is depletion of stratospheric ozone, leading to increased penetration of biologically damaging Solar ultraviolet-B (UVB) radiation to Earth's surface. Previous work has modeled the atmospheric chemistry effects of volcanic emission at the end-Permian. Here we use those results as input for detailed radiative transfer simulations to investigate changes in surface-level Solar irradiance in the ultraviolet-B, ultraviolet-A and photosynthetically available (visible light) wave bands. We then evaluate the potential biological effects using biological weighting functions. In addition to changes in ozone column density we also include gaseous sulfur dioxide (SO2) and sulfate aerosols. Ours is the first such study to include these factors and we find they have a significant impact on transmission of Solar radiation through the atmosphere. Inclusion of SO2 and aerosols greatly reduces the transmission of radiation across the ultraviolet and visible wavelengths, with subsequent reduction in biological impacts by UVB. We conclude that claims of a UVB mechanism for this extinction are likely overstated. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.10188v1-abstract-full').style.display = 'none'; document.getElementById('1911.10188v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 22 November, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">Submitted to Nature Geoscience</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1911.06972">arXiv:1911.06972</a> <span> [<a href="https://arxiv.org/pdf/1911.06972">pdf</a>, <a href="https://arxiv.org/format/1911.06972">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 Detectors">physics.ins-det</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/10.1088/1742-6596/1668/1/012013">10.1088/1742-6596/1668/1/012013 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Review and new concepts for neutron-capture measurements of astrophysical interest </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Domingo-Pardo%2C+C">C. Domingo-Pardo</a>, <a href="/search/physics?searchtype=author&query=Babiano-Suarez%2C+V">V. Babiano-Suarez</a>, <a href="/search/physics?searchtype=author&query=Balibrea-Correa%2C+J">J. Balibrea-Correa</a>, <a href="/search/physics?searchtype=author&query=Caballero%2C+L">L. Caballero</a>, <a href="/search/physics?searchtype=author&query=Ladarescu%2C+I">I. Ladarescu</a>, <a href="/search/physics?searchtype=author&query=Lerendegui-Marco%2C+J">J. Lerendegui-Marco</a>, <a href="/search/physics?searchtype=author&query=Tain%2C+J+L">J. L. Tain</a>, <a href="/search/physics?searchtype=author&query=Calvi%C3%B1o%2C+F">F. Calvi帽o</a>, <a href="/search/physics?searchtype=author&query=Casanovas%2C+A">A. Casanovas</a>, <a href="/search/physics?searchtype=author&query=Segarra%2C+A">A. Segarra</a>, <a href="/search/physics?searchtype=author&query=Tarife%C3%B1o-Saldivia%2C+A+E">A. E. Tarife帽o-Saldivia</a>, <a href="/search/physics?searchtype=author&query=Guerrero%2C+C">C. Guerrero</a>, <a href="/search/physics?searchtype=author&query=Mill%C3%A1n-Callado%2C+M+A">M. A. Mill谩n-Callado</a>, <a href="/search/physics?searchtype=author&query=Quesada%2C+J+M">J. M. Quesada</a>, <a href="/search/physics?searchtype=author&query=Rodr%C3%ADguez-Gonz%C3%A1lez%2C+M+T">M. T. Rodr铆guez-Gonz谩lez</a>, <a href="/search/physics?searchtype=author&query=Aberle%2C+O">O. Aberle</a>, <a href="/search/physics?searchtype=author&query=Alcayne%2C+V">V. Alcayne</a>, <a href="/search/physics?searchtype=author&query=Amaducci%2C+S">S. Amaducci</a>, <a href="/search/physics?searchtype=author&query=Andrzejewski%2C+J">J. Andrzejewski</a>, <a href="/search/physics?searchtype=author&query=Audouin%2C+L">L. Audouin</a>, <a href="/search/physics?searchtype=author&query=Bacak%2C+M">M. Bacak</a>, <a href="/search/physics?searchtype=author&query=Barbagallo%2C+M">M. Barbagallo</a>, <a href="/search/physics?searchtype=author&query=Bennett%2C+S">S. Bennett</a>, <a href="/search/physics?searchtype=author&query=Berthoumieux%2C+E">E. Berthoumieux</a>, <a href="/search/physics?searchtype=author&query=Bosnar%2C+D">D. Bosnar</a> , et al. (106 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="1911.06972v1-abstract-short" style="display: inline;"> The idea of slow-neutron capture nucleosynthesis formulated in 1957 triggered a tremendous experimental effort in different laboratories worldwide to measure the relevant nuclear physics input quantities, namely ($n,纬$) cross sections over the stellar temperature range (from few eV up to several hundred keV) for most of the isotopes involved from Fe up to Bi. A brief historical review focused on t… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.06972v1-abstract-full').style.display = 'inline'; document.getElementById('1911.06972v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1911.06972v1-abstract-full" style="display: none;"> The idea of slow-neutron capture nucleosynthesis formulated in 1957 triggered a tremendous experimental effort in different laboratories worldwide to measure the relevant nuclear physics input quantities, namely ($n,纬$) cross sections over the stellar temperature range (from few eV up to several hundred keV) for most of the isotopes involved from Fe up to Bi. A brief historical review focused on total energy detectors will be presented to illustrate how, advances in instrumentation have led, over the years, to the assessment and discovery of many new aspects of $s$-process nucleosynthesis and to the progressive refinement of theoretical models of stellar evolution. A summary will be presented on current efforts to develop new detection concepts, such as the Total-Energy Detector with $纬$-ray imaging capability (i-TED). The latter is based on the simultaneous combination of Compton imaging with neutron time-of-flight (TOF) techniques, in order to achieve a superior level of sensitivity and selectivity in the measurement of stellar neutron capture rates. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1911.06972v1-abstract-full').style.display = 'none'; document.getElementById('1911.06972v1-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, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">Nuclear Physics in Astrophysics IX - Conference Proceedings</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1907.10558">arXiv:1907.10558</a> <span> [<a href="https://arxiv.org/pdf/1907.10558">pdf</a>, <a href="https://arxiv.org/format/1907.10558">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="Computational Physics">physics.comp-ph</span> </div> </div> <p class="title is-5 mathjax"> Advanced Astrophysics Discovery Technology in the Era of Data Driven Astronomy </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Barry%2C+R+K">Richard K. Barry</a>, <a href="/search/physics?searchtype=author&query=Babu%2C+J+G">Jogesh G. Babu</a>, <a href="/search/physics?searchtype=author&query=Baker%2C+J+G">John G. Baker</a>, <a href="/search/physics?searchtype=author&query=Feigelson%2C+E+D">Eric D. Feigelson</a>, <a href="/search/physics?searchtype=author&query=Kaur%2C+A">Amanpreet Kaur</a>, <a href="/search/physics?searchtype=author&query=Kogut%2C+A+J">Alan J. Kogut</a>, <a href="/search/physics?searchtype=author&query=Kraemer%2C+S+B">Steven B. Kraemer</a>, <a href="/search/physics?searchtype=author&query=Mason%2C+J+P">James P. Mason</a>, <a href="/search/physics?searchtype=author&query=Mehrotra%2C+P">Piyush Mehrotra</a>, <a href="/search/physics?searchtype=author&query=Olmschenk%2C+G">Gregory Olmschenk</a>, <a href="/search/physics?searchtype=author&query=Schnittman%2C+J+D">Jeremy D. Schnittman</a>, <a href="/search/physics?searchtype=author&query=Stokholm%2C+A">Amalie Stokholm</a>, <a href="/search/physics?searchtype=author&query=Switzer%2C+E+R">Eric R. Switzer</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+A">Brian A. Thomas</a>, <a href="/search/physics?searchtype=author&query=Walker%2C+R+J">Raymond J. Walker</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="1907.10558v1-abstract-short" style="display: inline;"> Experience suggests that structural issues in how institutional Astrophysics approaches data-driven science and the development of discovery technology may be hampering the community's ability to respond effectively to a rapidly changing environment in which increasingly complex, heterogeneous datasets are challenging our existing information infrastructure and traditional approaches to analysis.… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.10558v1-abstract-full').style.display = 'inline'; document.getElementById('1907.10558v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1907.10558v1-abstract-full" style="display: none;"> Experience suggests that structural issues in how institutional Astrophysics approaches data-driven science and the development of discovery technology may be hampering the community's ability to respond effectively to a rapidly changing environment in which increasingly complex, heterogeneous datasets are challenging our existing information infrastructure and traditional approaches to analysis. We stand at the confluence of a new epoch of multimessenger science, remote co-location of data and processing power and new observing strategies based on miniaturized spacecraft. Significant effort will be required by the community to adapt to this rapidly evolving range of possible discovery moduses. In the suggested creation of a new Astrophysics element, Advanced Astrophysics Discovery Technology, we offer an affirmative solution that places the visibility of discovery technologies at a level that we suggest is fully commensurate with their importance to the future of the field. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1907.10558v1-abstract-full').style.display = 'none'; document.getElementById('1907.10558v1-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 July, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">White paper submitted to the ASTRO2020 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/1905.13269">arXiv:1905.13269</a> <span> [<a href="https://arxiv.org/pdf/1905.13269">pdf</a>, <a href="https://arxiv.org/format/1905.13269">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Physics Education">physics.ed-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/10.1119/10.0000014">10.1119/10.0000014 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Quantum matrix diagonalization visualized </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Randles%2C+K">Kevin Randles</a>, <a href="/search/physics?searchtype=author&query=Schroeder%2C+D+V">Daniel V. Schroeder</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+R">Bruce R. Thomas</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="1905.13269v1-abstract-short" style="display: inline;"> We show how to visualize the process of diagonalizing the Hamiltonian matrix to find the energy eigenvalues and eigenvectors of a generic one-dimensional quantum system. Starting in the familiar sine-wave basis of an embedding infinite square well, we display the Hamiltonian matrix graphically with the basis functions alongside. Each step in the diagonalization process consists of selecting a nonz… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.13269v1-abstract-full').style.display = 'inline'; document.getElementById('1905.13269v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1905.13269v1-abstract-full" style="display: none;"> We show how to visualize the process of diagonalizing the Hamiltonian matrix to find the energy eigenvalues and eigenvectors of a generic one-dimensional quantum system. Starting in the familiar sine-wave basis of an embedding infinite square well, we display the Hamiltonian matrix graphically with the basis functions alongside. Each step in the diagonalization process consists of selecting a nonzero off-diagonal matrix element, then rotating the two corresponding basis vectors in their own subspace until this element is zero. We provide Mathematica code to display the effects of these rotations on both the matrix and the basis functions. As an electronic supplement we also provide a JavaScript web app to interactively carry out this process. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1905.13269v1-abstract-full').style.display = 'none'; document.getElementById('1905.13269v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 30 May, 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">6 pages, 2 figures. Submitted to the American Journal of Physics</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Am. J. Phys. 87(11), 857-861 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.04589">arXiv:1903.04589</a> <span> [<a href="https://arxiv.org/pdf/1903.04589">pdf</a>, <a href="https://arxiv.org/format/1903.04589">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Solar and Stellar Astrophysics">astro-ph.SR</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Nuclear Experiment">nucl-ex</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"> Near-Earth Supernova Explosions: Evidence, Implications, and Opportunities </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Fields%2C+B+D">Brian D. Fields</a>, <a href="/search/physics?searchtype=author&query=Ellis%2C+J+R">John R. Ellis</a>, <a href="/search/physics?searchtype=author&query=Binns%2C+W+R">Walter R. Binns</a>, <a href="/search/physics?searchtype=author&query=Breitschwerdt%2C+D">Dieter Breitschwerdt</a>, <a href="/search/physics?searchtype=author&query=de+Nolfo%2C+G+A">Georgia A. de Nolfo</a>, <a href="/search/physics?searchtype=author&query=Diehl%2C+R">Roland Diehl</a>, <a href="/search/physics?searchtype=author&query=Dwarkadas%2C+V+V">Vikram V. Dwarkadas</a>, <a href="/search/physics?searchtype=author&query=Ertel%2C+A">Adrienne Ertel</a>, <a href="/search/physics?searchtype=author&query=Faestermann%2C+T">Thomas Faestermann</a>, <a href="/search/physics?searchtype=author&query=Feige%2C+J">Jenny Feige</a>, <a href="/search/physics?searchtype=author&query=Fitoussi%2C+C">Caroline Fitoussi</a>, <a href="/search/physics?searchtype=author&query=Frisch%2C+P">Priscilla Frisch</a>, <a href="/search/physics?searchtype=author&query=Graham%2C+D">David Graham</a>, <a href="/search/physics?searchtype=author&query=Haley%2C+B">Brian Haley</a>, <a href="/search/physics?searchtype=author&query=Heger%2C+A">Alexander Heger</a>, <a href="/search/physics?searchtype=author&query=Hillebrandt%2C+W">Wolfgang Hillebrandt</a>, <a href="/search/physics?searchtype=author&query=Israel%2C+M+H">Martin H. Israel</a>, <a href="/search/physics?searchtype=author&query=Janka%2C+T">Thomas Janka</a>, <a href="/search/physics?searchtype=author&query=Kachelriess%2C+M">Michael Kachelriess</a>, <a href="/search/physics?searchtype=author&query=Korschinek%2C+G">Gunther Korschinek</a>, <a href="/search/physics?searchtype=author&query=Limongi%2C+M">Marco Limongi</a>, <a href="/search/physics?searchtype=author&query=Lugaro%2C+M">Maria Lugaro</a>, <a href="/search/physics?searchtype=author&query=Marinho%2C+F">Franciole Marinho</a>, <a href="/search/physics?searchtype=author&query=Melott%2C+A">Adrian Melott</a>, <a href="/search/physics?searchtype=author&query=Mewaldt%2C+R+A">Richard A. Mewaldt</a> , et al. (14 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="1903.04589v1-abstract-short" style="display: inline;"> There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope 60Fe in widespread deep-ocean samples, as well as in the lunar regolith and cosmic rays. This is the first established example of a specific dated astrophysical event outside the Solar System having a measurable impact o… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.04589v1-abstract-full').style.display = 'inline'; document.getElementById('1903.04589v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.04589v1-abstract-full" style="display: none;"> There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope 60Fe in widespread deep-ocean samples, as well as in the lunar regolith and cosmic rays. This is the first established example of a specific dated astrophysical event outside the Solar System having a measurable impact on the Earth, offering new probes of stellar evolution, nuclear astrophysics, the astrophysics of the solar neighborhood, cosmic-ray sources and acceleration, multi-messenger astronomy, and astrobiology. Interdisciplinary connections reach broadly to include heliophysics, geology, and evolutionary biology. Objectives for the future include pinning down the nature and location of the established near-Earth supernova explosions, seeking evidence for others, and searching for other short-lived isotopes such as 26Al and 244Pu. The unique information provided by geological and lunar detections of radioactive 60Fe to assess nearby supernova explosions make now a compelling time for the astronomy community to advocate for supporting multi-disciplinary, cross-cutting research programs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.04589v1-abstract-full').style.display = 'none'; document.getElementById('1903.04589v1-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 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 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">11 pages, 2 figures. Astro2020 Science White Paper submitted to the 2020 Decadal Survey on Astronomy and Astrophysics</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1903.01501">arXiv:1903.01501</a> <span> [<a href="https://arxiv.org/pdf/1903.01501">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/10.1086/703418">10.1086/703418 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> From cosmic explosions to terrestrial fires? </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="1903.01501v1-abstract-short" style="display: inline;"> Multiple lines of evidence point to one or more moderately nearby supernovae, with the strongest signal ~2.6 Ma. We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent lightning, and therefore an increase in nitrate deposition and in wildfires. The potential exists for a large increase in the pre-human nitrate… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.01501v1-abstract-full').style.display = 'inline'; document.getElementById('1903.01501v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1903.01501v1-abstract-full" style="display: none;"> Multiple lines of evidence point to one or more moderately nearby supernovae, with the strongest signal ~2.6 Ma. We build on previous work to argue for the likelihood of cosmic ray ionization of the atmosphere and electron cascades leading to more frequent lightning, and therefore an increase in nitrate deposition and in wildfires. The potential exists for a large increase in the pre-human nitrate flux onto the surface, which has previously been argued to lead to CO2 drawdown and cooling of the climate. Evidence for increased wildfires exists in an increase in soot and carbon deposits over the relevant period. The wildfires would have contributed to the transition from forest to savanna in northeast Africa, long argued to have been a factor in the evolution of hominin bipedalism. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1903.01501v1-abstract-full').style.display = 'none'; document.getElementById('1903.01501v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 4 March, 2019; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2019. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Comments:</span> <span class="has-text-grey-dark mathjax">20 pages, 3 figures. To be published in the Journal of Geology</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Journal of Geology, 127, 475-481 (2019) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1805.09594">arXiv:1805.09594</a> <span> [<a href="https://arxiv.org/pdf/1805.09594">pdf</a>, <a href="https://arxiv.org/format/1805.09594">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/epjconf/201920301005">10.1051/epjconf/201920301005 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> The deteriorating effect of plasma density fluctuations on microwave beam quality </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=K%C3%B6hn%2C+A">Alf K枚hn</a>, <a href="/search/physics?searchtype=author&query=Austin%2C+M+E">Max E. Austin</a>, <a href="/search/physics?searchtype=author&query=Brookman%2C+M+W">Michael W. Brookman</a>, <a href="/search/physics?searchtype=author&query=Gentle%2C+K+W">Kenneth W. Gentle</a>, <a href="/search/physics?searchtype=author&query=Guidi%2C+L">Lorenzo Guidi</a>, <a href="/search/physics?searchtype=author&query=Holzhauer%2C+E">Eberhard Holzhauer</a>, <a href="/search/physics?searchtype=author&query=La+Haye%2C+R+J">Rob J. La Haye</a>, <a href="/search/physics?searchtype=author&query=Leddy%2C+J+B">Jarrod B. Leddy</a>, <a href="/search/physics?searchtype=author&query=Maj%2C+O">Omar Maj</a>, <a href="/search/physics?searchtype=author&query=Petty%2C+C+C">Craig C. Petty</a>, <a href="/search/physics?searchtype=author&query=Poli%2C+E">Emanuele Poli</a>, <a href="/search/physics?searchtype=author&query=Rhodes%2C+T+L">Terry L. Rhodes</a>, <a href="/search/physics?searchtype=author&query=Snicker%2C+A">Antti Snicker</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+M+B">Matthew B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Vann%2C+R+G+L">Roddy G. L. Vann</a>, <a href="/search/physics?searchtype=author&query=Weber%2C+H">Hannes Weber</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="1805.09594v1-abstract-short" style="display: inline;"> Turbulent plasma edge density fluctuations can broaden a traversing microwave beam degrading its quality. This can be a problem for scenarios relying on a high spatial localization of the deposition of injected microwave power, like controlling MHD instabilities. Here we present numerical estimations of the scattering of a microwave beam by density fluctuations over a large parameter range, includ… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.09594v1-abstract-full').style.display = 'inline'; document.getElementById('1805.09594v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1805.09594v1-abstract-full" style="display: none;"> Turbulent plasma edge density fluctuations can broaden a traversing microwave beam degrading its quality. This can be a problem for scenarios relying on a high spatial localization of the deposition of injected microwave power, like controlling MHD instabilities. Here we present numerical estimations of the scattering of a microwave beam by density fluctuations over a large parameter range, including extrapolations to ITER. Two codes are used, the full-wave code IPF-FDMC and the wave kinetic equation solver WKBeam. A successful comparison between beam broadening obtained from DIII-D experiments and corresponding full-wave simulations is shown. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1805.09594v1-abstract-full').style.display = 'none'; document.getElementById('1805.09594v1-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 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">EPJ Web of Conferences, EC-20 2018 Proceedings, submitted</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1712.02730">arXiv:1712.02730</a> <span> [<a href="https://arxiv.org/pdf/1712.02730">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Biological Physics">physics.bio-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/10.1111/let.12256">10.1111/let.12256 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Terrestrial effects of moderately nearby supernovae </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="1712.02730v1-abstract-short" style="display: inline;"> Recent data indicate one or more moderately nearby supernovae in the early Pleistocene, with additional events likely in the Miocene. This has motivated more detailed computations, using new information about the nature of supernovae and the distances of these events to describe in more detail the sorts of effects that are indicated at the Earth. This short communication/review is designed to desc… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.02730v1-abstract-full').style.display = 'inline'; document.getElementById('1712.02730v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1712.02730v1-abstract-full" style="display: none;"> Recent data indicate one or more moderately nearby supernovae in the early Pleistocene, with additional events likely in the Miocene. This has motivated more detailed computations, using new information about the nature of supernovae and the distances of these events to describe in more detail the sorts of effects that are indicated at the Earth. This short communication/review is designed to describe some of these effects so that they may possibly be related to changes in the biota around these times. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1712.02730v1-abstract-full').style.display = 'none'; document.getElementById('1712.02730v1-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 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">2 figures; to be published in Lethaia</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Lethaia 51, 325-329 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1711.00410">arXiv:1711.00410</a> <span> [<a href="https://arxiv.org/pdf/1711.00410">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/10.1089/ast.2017.1730">10.1089/ast.2017.1730 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Photobiological effects at Earth's surface following a 50 pc Supernova </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="1711.00410v1-abstract-short" style="display: inline;"> We investigated the potential biological impacts at Earth's surface of stratospheric O3 depletion caused by nearby supernovae known to have occurred about 2.5 and 8 million years ago at about 50 pc distance. New and previously published atmospheric chemistry modeling results were combined with radiative transfer modeling to determine changes in surface-level Solar irradiance and biological respons… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1711.00410v1-abstract-full').style.display = 'inline'; document.getElementById('1711.00410v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1711.00410v1-abstract-full" style="display: none;"> We investigated the potential biological impacts at Earth's surface of stratospheric O3 depletion caused by nearby supernovae known to have occurred about 2.5 and 8 million years ago at about 50 pc distance. New and previously published atmospheric chemistry modeling results were combined with radiative transfer modeling to determine changes in surface-level Solar irradiance and biological responses. We find that UVB irradiance is increased by a factor of 1.1 to 2.8, with large variation in latitude, and seasonally at high latitude regions. Changes in UVA and PAR (visible light) are much smaller. DNA damage (in vitro) is increased by factors similar to UVB, while other biological impacts (erythema, skin cancer, cataracts, marine phytoplankton photosynthesis inhibition, and plant damage) are increased by smaller amounts. We conclude that biological impacts due to increased UV irradiance in this SN case are not mass-extinction level, but might be expected to contribute to changes in species abundances; this result fits well with species turnover observed around the Pliocene-Pleistocene boundary. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1711.00410v1-abstract-full').style.display = 'none'; document.getElementById('1711.00410v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 November, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> November 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">Accepted for publication in Astrobiology</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Astrobiology, Vol. 18, 2018 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1710.03503">arXiv:1710.03503</a> <span> [<a href="https://arxiv.org/pdf/1710.03503">pdf</a>, <a href="https://arxiv.org/format/1710.03503">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> </div> </div> <p class="title is-5 mathjax"> Resolving ECRH deposition broadening due to edge turbulence in DIII-D by heat deposition measurement </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Brookman%2C+M+W">Michael W Brookman</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+M+B">Matthew B Thomas</a>, <a href="/search/physics?searchtype=author&query=Leddy%2C+J">Jarrod Leddy</a>, <a href="/search/physics?searchtype=author&query=Petty%2C+C+C">C Craig Petty</a>, <a href="/search/physics?searchtype=author&query=La+Haye%2C+R+J">Robert J La Haye</a>, <a href="/search/physics?searchtype=author&query=Barada%2C+K">K Barada</a>, <a href="/search/physics?searchtype=author&query=Rhodes%2C+T+L">Terry L Rhodes</a>, <a href="/search/physics?searchtype=author&query=Yan%2C+Z">Zheng Yan</a>, <a href="/search/physics?searchtype=author&query=Austin%2C+M+E">Max E Austin</a>, <a href="/search/physics?searchtype=author&query=Vann%2C+R+G+L">Roddy G L Vann</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="1710.03503v1-abstract-short" style="display: inline;"> Interaction between microwave power, used for local heating and mode control, and density fluctuations can produce a broadening of the injected beam, as confirmed in experiment and simulation. Increased power deposition width could impact suppression of tearing mode structures on ITER. This work discusses the experimental portion of an effort to understand scattering of injected microwaves by turb… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.03503v1-abstract-full').style.display = 'inline'; document.getElementById('1710.03503v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.03503v1-abstract-full" style="display: none;"> Interaction between microwave power, used for local heating and mode control, and density fluctuations can produce a broadening of the injected beam, as confirmed in experiment and simulation. Increased power deposition width could impact suppression of tearing mode structures on ITER. This work discusses the experimental portion of an effort to understand scattering of injected microwaves by turbulence on the DIII-D tokamak. The corresponding theoretical modeling work can be found in M.B. Thomas et. al.: Submitted to Nuclear Fusion (2017)[Author Note - this paper to be published in same journal]. In a set of perturbative heat transport experiments, tokamak edge millimeter-scale fluctuation levels and microwave heat deposition are measured simultaneously. Beam broadening is separated from heat transport through fitting of modulated fluxes. Electron temperature measurements from a 500 kHz, 48-channel ECE radiometer are Fourier analyzed and used to calculate a deposition-dependent flux. Consistency of this flux with a transport model is evaluated. A diffusive and convective transport solution is linearized and compared with energy conservation-derived fluxes. Comparison between these two forms of heat flux is used to evaluate the quality of ECRF deposition profiles, and fitting finds a significant broadening of 1D equilibrium ray tracing calculations from the benchmarked TORAY-GA ray tracing code is needed. The physical basis, cross-validation, and application of the heat flux method is presented. The method is applied to a range of DIII-D discharges and finds a broadening factor of the deposition profile width which scales linearly with edge density fluctuation level. These experimental results are found to be consistent with the full-wave beam broadening measured by the 3D full wave simulations in the same discharges. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.03503v1-abstract-full').style.display = 'none'; document.getElementById('1710.03503v1-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, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 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">21 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/1710.03028">arXiv:1710.03028</a> <span> [<a href="https://arxiv.org/pdf/1710.03028">pdf</a>, <a href="https://arxiv.org/format/1710.03028">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> </div> </div> <p class="title is-5 mathjax"> Resolving ECRH deposition broadening due to edge turbulence in DIII-D by 3D full-wave simulations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+M+B">Matthew B Thomas</a>, <a href="/search/physics?searchtype=author&query=Brookman%2C+M+W">Michael W Brookman</a>, <a href="/search/physics?searchtype=author&query=Austin%2C+M+E">Max E Austin</a>, <a href="/search/physics?searchtype=author&query=K%C3%B6hn%2C+A">Alf K枚hn</a>, <a href="/search/physics?searchtype=author&query=La+Haye%2C+R+J">Robert J La Haye</a>, <a href="/search/physics?searchtype=author&query=Leddy%2C+J+B">Jarrod B Leddy</a>, <a href="/search/physics?searchtype=author&query=Vann%2C+R+G+L">Roddy G L Vann</a>, <a href="/search/physics?searchtype=author&query=Yan%2C+Z">Zheng Yan</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="1710.03028v1-abstract-short" style="display: inline;"> Edge plasma density fluctuations are shown to have a significant effect on the electron cyclotron resonance heating (ECRH) beam in the DIII-D tokamak. Experimental measurements of the ECRH deposition profile have been taken in three operating scenarios: L-mode, H-mode and negative triangularity. Each scenario corresponds to distinct turbulence characteristics in the edge region through which the b… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.03028v1-abstract-full').style.display = 'inline'; document.getElementById('1710.03028v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1710.03028v1-abstract-full" style="display: none;"> Edge plasma density fluctuations are shown to have a significant effect on the electron cyclotron resonance heating (ECRH) beam in the DIII-D tokamak. Experimental measurements of the ECRH deposition profile have been taken in three operating scenarios: L-mode, H-mode and negative triangularity. Each scenario corresponds to distinct turbulence characteristics in the edge region through which the beam must propagate. The measured ECRH deposition profile is significantly broadened by comparison to the profile predicted by the ray tracing code TORAY-GA and has been shown to scale with the severity of edge turbulence. Conventional ray tracing does not include the effects of turbulence and therefore a 3D full-wave cold plasma finite difference time domain code EMIT-3D is presented and used for the simulations. The turbulence is generated through the Hermes model in the BOUT++ framework which takes as input the measured time averaged electron density, temperature and magnetic field profiles for the specific shot in question. The simulated turbulence is constrained to match the experimentally measured (by use of the BES and DBS systems) correlation length and normalised fluctuation levels. The predictions of the beam broadening from the simulations are found to agree very well with the experimentally-observed broadening in all cases: L-mode, H-mode and negative triangularity. Due to the large gradients within the H-mode edge, the resolution uncertainty and error in the measurement from Thomson scattering and BES diagnostics result in a spread in the simulated turbulence amplitude. In light of this a parameter scan through the range in experimental diagnostic measurement uncertainty has been conducted to explore the impact on beam broadening predictions. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1710.03028v1-abstract-full').style.display = 'none'; document.getElementById('1710.03028v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 9 October, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> October 2017. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1705.06258">arXiv:1705.06258</a> <span> [<a href="https://arxiv.org/pdf/1705.06258">pdf</a>, <a href="https://arxiv.org/format/1705.06258">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</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="High Energy Physics - Experiment">hep-ex</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1029/2017JD027931">10.1029/2017JD027931 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Gamma-ray Showers Observed at Ground Level in Coincidence With Downward Lightning Leaders </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Abbasi%2C+R+U">R. U. Abbasi</a>, <a href="/search/physics?searchtype=author&query=Abu-Zayyad%2C+T">T. Abu-Zayyad</a>, <a href="/search/physics?searchtype=author&query=Allen%2C+M">M. Allen</a>, <a href="/search/physics?searchtype=author&query=Barcikowski%2C+E">E. Barcikowski</a>, <a href="/search/physics?searchtype=author&query=Belz%2C+J+W">J. W. Belz</a>, <a href="/search/physics?searchtype=author&query=Bergman%2C+D+R">D. R. Bergman</a>, <a href="/search/physics?searchtype=author&query=Blake%2C+S+A">S. A. Blake</a>, <a href="/search/physics?searchtype=author&query=Byrne%2C+M">M. Byrne</a>, <a href="/search/physics?searchtype=author&query=Cady%2C+R">R. Cady</a>, <a href="/search/physics?searchtype=author&query=Cheon%2C+B+G">B. G. Cheon</a>, <a href="/search/physics?searchtype=author&query=Chiba%2C+J">J. Chiba</a>, <a href="/search/physics?searchtype=author&query=Chikawa%2C+M">M. Chikawa</a>, <a href="/search/physics?searchtype=author&query=Fujii%2C+T">T. Fujii</a>, <a href="/search/physics?searchtype=author&query=Fukushima%2C+M">M. Fukushima</a>, <a href="/search/physics?searchtype=author&query=Furlich%2C+G">G. Furlich</a>, <a href="/search/physics?searchtype=author&query=Goto%2C+T">T. Goto</a>, <a href="/search/physics?searchtype=author&query=Hanlon%2C+W">W. Hanlon</a>, <a href="/search/physics?searchtype=author&query=Hayashi%2C+Y">Y. Hayashi</a>, <a href="/search/physics?searchtype=author&query=Hayashida%2C+N">N. Hayashida</a>, <a href="/search/physics?searchtype=author&query=Hibino%2C+K">K. Hibino</a>, <a href="/search/physics?searchtype=author&query=Honda%2C+K">K. Honda</a>, <a href="/search/physics?searchtype=author&query=Ikeda%2C+D">D. Ikeda</a>, <a href="/search/physics?searchtype=author&query=Inoue%2C+N">N. Inoue</a>, <a href="/search/physics?searchtype=author&query=Ishii%2C+T">T. Ishii</a>, <a href="/search/physics?searchtype=author&query=Ito%2C+H">H. Ito</a> , et al. (99 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="1705.06258v3-abstract-short" style="display: inline;"> Bursts of gamma ray showers have been observed in coincidence with downward propagating negative leaders in lightning flashes by the Telescope Array Surface Detector (TASD). The TASD is a 700~square kilometer cosmic ray observatory located in southwestern Utah, U.S.A. In data collected between 2014 and 2016, correlated observations showing the structure and temporal development of three shower-pro… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.06258v3-abstract-full').style.display = 'inline'; document.getElementById('1705.06258v3-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1705.06258v3-abstract-full" style="display: none;"> Bursts of gamma ray showers have been observed in coincidence with downward propagating negative leaders in lightning flashes by the Telescope Array Surface Detector (TASD). The TASD is a 700~square kilometer cosmic ray observatory located in southwestern Utah, U.S.A. In data collected between 2014 and 2016, correlated observations showing the structure and temporal development of three shower-producing flashes were obtained with a 3D lightning mapping array, and electric field change measurements were obtained for an additional seven flashes, in both cases co-located with the TASD. National Lightning Detection Network (NLDN) information was also used throughout. The showers arrived in a sequence of 2--5 short-duration ($\le$10~$渭$s) bursts over time intervals of several hundred microseconds, and originated at an altitude of $\simeq$3--5 kilometers above ground level during the first 1--2 ms of downward negative leader breakdown at the beginning of cloud-to-ground lightning flashes. The shower footprints, associated waveforms and the effect of atmospheric propagation indicate that the showers consist primarily of downward-beamed gamma radiation. This has been supported by GEANT simulation studies, which indicate primary source fluxes of $\simeq$$10^{12}$--$10^{14}$ photons for $16^{\circ}$ half-angle beams. We conclude that the showers are terrestrial gamma-ray flashes (TGFs), similar to those observed by satellites, but that the ground-based observations are more representative of the temporal source activity and are also more sensitive than satellite observations, which detect only the most powerful TGFs. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1705.06258v3-abstract-full').style.display = 'none'; document.getElementById('1705.06258v3-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 May, 2018; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 17 May, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> J. Geophys. Res. Atmos., 123 (2018) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1703.05182">arXiv:1703.05182</a> <span> [<a href="https://arxiv.org/pdf/1703.05182">pdf</a>, <a href="https://arxiv.org/format/1703.05182">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-ph</span> </div> <div class="is-inline-block" style="margin-left: 0.5rem"> <div class="tags has-addons"> <span class="tag is-dark is-size-7">doi</span> <span class="tag is-light is-size-7"><a class="" href="https://doi.org/10.1051/epjconf/201714701001">10.1051/epjconf/201714701001 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Perturbing microwave beams by plasma density fluctuations </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=K%C3%B6hn%2C+A">Alf K枚hn</a>, <a href="/search/physics?searchtype=author&query=Holzhauer%2C+E">Eberhard Holzhauer</a>, <a href="/search/physics?searchtype=author&query=Leddy%2C+J">Jarrod Leddy</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+M+B">Matthew B. Thomas</a>, <a href="/search/physics?searchtype=author&query=Vann%2C+R+G+L">Roddy G. L. Vann</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="1703.05182v1-abstract-short" style="display: inline;"> The propagation of microwaves across a turbulent plasma density layer is investigated with full-wave simulations. To properly represent a fusion edge-plasma, drift-wave turbulence is considered based on the Hasegawa-Wakatani model. Scattering and broadening of a microwave beam whose amplitude distribution is of Gaussian shape is studied in detail as a function of certain turbulence properties. Par… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.05182v1-abstract-full').style.display = 'inline'; document.getElementById('1703.05182v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1703.05182v1-abstract-full" style="display: none;"> The propagation of microwaves across a turbulent plasma density layer is investigated with full-wave simulations. To properly represent a fusion edge-plasma, drift-wave turbulence is considered based on the Hasegawa-Wakatani model. Scattering and broadening of a microwave beam whose amplitude distribution is of Gaussian shape is studied in detail as a function of certain turbulence properties. Parameters leading to the strongest deterioration of the microwave beam are identified and implications for existing experiments are given. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1703.05182v1-abstract-full').style.display = 'none'; document.getElementById('1703.05182v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 15 March, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> March 2017. </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> EPJ Web of Conferences 147, 01001 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1702.04365">arXiv:1702.04365</a> <span> [<a href="https://arxiv.org/pdf/1702.04365">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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="Geophysics">physics.geo-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/aa6c57">10.3847/1538-4357/aa6c57 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> A supernova at 50 pc: Effects on the Earth's atmosphere and biota </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">A. L Melott</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">B. C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Kachelriess%2C+M">M. Kachelriess</a>, <a href="/search/physics?searchtype=author&query=Semikoz%2C+D+V">D. V. Semikoz</a>, <a href="/search/physics?searchtype=author&query=Overholt%2C+A+C">A. C. Overholt</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="1702.04365v2-abstract-short" style="display: inline;"> Recent 60Fe results have suggested that the estimated distances of supernovae in the last few million years should be reduced from 100 pc to 50 pc. Two events or series of events are suggested, one about 2.7 million years to 1.7 million years ago, and another may at 6.5 to 8.7 million years ago. We ask what effects such supernovae are expected to have on the terrestrial atmosphere and biota. Assum… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.04365v2-abstract-full').style.display = 'inline'; document.getElementById('1702.04365v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1702.04365v2-abstract-full" style="display: none;"> Recent 60Fe results have suggested that the estimated distances of supernovae in the last few million years should be reduced from 100 pc to 50 pc. Two events or series of events are suggested, one about 2.7 million years to 1.7 million years ago, and another may at 6.5 to 8.7 million years ago. We ask what effects such supernovae are expected to have on the terrestrial atmosphere and biota. Assuming that the Local Bubble was formed before the event being considered, and that the supernova and the Earth were both inside a weak, disordered magnetic field at that time, TeV-PeV cosmic rays at Earth will increase by a factor of a few hundred. Tropospheric ionization will increase proportionately, and the overall muon radiation load on terrestrial organisms will increase by a factor of 150. All return to pre-burst levels within 10kyr. In the case of an ordered magnetic field, effects depend strongly on the field orientation. The upper bound in this case is with a largely coherent field aligned along the line of sight to the supernova, in which case TeV-PeV cosmic ray flux increases are 10^4; in the case of a transverse field they are below current levels. We suggest a substantial increase in the extended effects of supernovae on Earth and in the lethal distance estimate; more work is needed.This paper is an explicit followup to Thomas et al. (2016). We also here provide more detail on the computational procedures used in both works. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1702.04365v2-abstract-full').style.display = 'none'; document.getElementById('1702.04365v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 7 April, 2017; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 14 February, 2017; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">5 figures. Revised version to be published in ApJ</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> ApJ 840 105 (2017) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1608.07512">arXiv:1608.07512</a> <span> [<a href="https://arxiv.org/pdf/1608.07512">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-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/10.1016/j.epsl.2016.08.014">10.1016/j.epsl.2016.08.014 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Atmospheric constituents and surface-level UVB: implications for a paleoaltimetry proxy and attempts to reconstruct UV exposure during volcanic episodes </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Goracke%2C+B+D">Byron D. Goracke</a>, <a href="/search/physics?searchtype=author&query=Dalton%2C+S+M">Sean M. Dalton</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="1608.07512v1-abstract-short" style="display: inline;"> Chemical and morphological features of spores and pollens have been linked to changes in solar ultraviolet radiation (specifically UVB, 280-315 nm) at Earth's surface. Variation in UVB exposure as inferred from these features has been suggested as a proxy for paleoaltitude. While UVB irradiance does increase with altitude above sea level, a number of other factors affect the irradiance at any give… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.07512v1-abstract-full').style.display = 'inline'; document.getElementById('1608.07512v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1608.07512v1-abstract-full" style="display: none;"> Chemical and morphological features of spores and pollens have been linked to changes in solar ultraviolet radiation (specifically UVB, 280-315 nm) at Earth's surface. Variation in UVB exposure as inferred from these features has been suggested as a proxy for paleoaltitude. While UVB irradiance does increase with altitude above sea level, a number of other factors affect the irradiance at any given place and time. In this modeling study we use the TUV atmospheric radiative transfer model to investigate dependence of surface-level UVB irradiance and relative biological impact on a number of constituents in Earth's atmosphere that are variable over long and short time periods. We consider changes in O3 column density, and SO2 and sulfate aerosols due to periods of volcanic activity, including that associated with the formation of the Siberian Traps. We find that UVB irradiance may be highly variable under volcanic conditions and variations in several of these atmospheric constituents can easily mimic or overwhelm changes in UVB irradiance due to changes in altitude. On the other hand, we find that relative change with altitude is not very sensitive to different sets of atmospheric conditions. Any paleoaltitude proxy based on UVB exposure requires confidence that the samples under comparison were located at roughly the same latitude, under very similar O3 and SO2 columns, with similar atmospheric aerosol conditions. In general, accurate estimates of the surface-level UVB exposure at any time and location require detailed radiative transfer modeling taking into account a number of atmospheric factors; this result is important for paleoaltitude proxies as well as attempts to reconstruct the UV environment through geologic time and to tie extinctions, such as the end-Permian mass extinction, to UVB irradiance changes. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1608.07512v1-abstract-full').style.display = 'none'; document.getElementById('1608.07512v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 August, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> August 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">Access: http://authors.elsevier.com/a/1TcSd,Ig45ZtO</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1607.02980">arXiv:1607.02980</a> <span> [<a href="https://arxiv.org/pdf/1607.02980">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Biological Physics">physics.bio-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/10.1111/gcb.13356">10.1111/gcb.13356 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Reductions in Depth-integrated Picophytoplanktonic Photosynthesis Due to Inhibition by Ultraviolet and Photosynthetically Available Radiation: Global Predictions for $\textit{Prochlorococcus}$ and $\textit{Synechococcus}$ </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Neale%2C+P+J">Patrick J. Neale</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="1607.02980v1-abstract-short" style="display: inline;"> Phytoplankton photosynthesis in most natural waters is often inhibited by ultraviolet (UV) and intense photosynthetically available radiation (PAR) but the effects on ocean productivity have received little consideration aside from polar areas subject to periodic enhanced UV-B due to depletion of stratospheric ozone. Here we consider responses in the temperate and tropical mid-ocean regions typica… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.02980v1-abstract-full').style.display = 'inline'; document.getElementById('1607.02980v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1607.02980v1-abstract-full" style="display: none;"> Phytoplankton photosynthesis in most natural waters is often inhibited by ultraviolet (UV) and intense photosynthetically available radiation (PAR) but the effects on ocean productivity have received little consideration aside from polar areas subject to periodic enhanced UV-B due to depletion of stratospheric ozone. Here we consider responses in the temperate and tropical mid-ocean regions typically dominated by picophytoplankton including the prokaryotic lineages, $\textit{Prochlorococcus}$ and $\textit{Synechococcus}$. Spectral models of photosynthetic response for each lineage were constructed using model strains cultured at different growth irradiances and temperatures. In the model, inhibition becomes more severe once exposure exceeds a threshold (Emax) related to repair capacity. Model parameters are presented for $\textit{Prochlorococcus}$ adding to those previously presented for $\textit{Synechococcus}$. The models were applied to the estimation of mid-day, water-column photosynthesis based on an atmospheric model of spectral incident radiation, satellite-derived spectral water transparency and sea surface temperature. Comparing predictions integrated over the water column including versus excluding inhibition, production was 7-28% lower due to inhibition depending on strain and site conditions. Inhibition was consistently greater for $\textit{Prochlorococcus}$ compared to two strains of $\textit{Synechococcus}$. Considering only the surface mixed layer, production was inhibited 7-73%. Weighted by lineage abundance and daily PAR exposure, inhibition of full water column production averages around 20% for the modeled region of the Pacific with two-thirds of the inhibition due to UV. The results suggest more consideration is needed on inhibition effects, especially due to UV, which are largely excluded from present models of global phytoplankton production. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1607.02980v1-abstract-full').style.display = 'none'; document.getElementById('1607.02980v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> July 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">In press at Global Change Biology</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1606.08792">arXiv:1606.08792</a> <span> [<a href="https://arxiv.org/pdf/1606.08792">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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="Geophysics">physics.geo-ph</span> </div> </div> <p class="title is-5 mathjax"> Reply to comment by K.A. Duderstadt et al. on "Atmospheric ionization by high-fluence, hard spectrum solar proton events and their probable appearance in the ice core archive" </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Laird%2C+C+M">Claude M. Laird</a>, <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Neuenswander%2C+B">Ben Neuenswander</a>, <a href="/search/physics?searchtype=author&query=Atri%2C+D">Dimitra Atri</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="1606.08792v1-abstract-short" style="display: inline;"> Duderstadt et al. [2016b] comment that the Melott et al. [2016] study of nitrate formation by solar proton events (SPEs) and comparison with the ice core archive is "fundamentally flawed," because it does not include pre-existing HNO3 in the stratosphere. We show that they exaggerate both the enhancement predicted by our findings and pre-industrial HNO3 levels in their model, and fail to prove thi… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.08792v1-abstract-full').style.display = 'inline'; document.getElementById('1606.08792v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1606.08792v1-abstract-full" style="display: none;"> Duderstadt et al. [2016b] comment that the Melott et al. [2016] study of nitrate formation by solar proton events (SPEs) and comparison with the ice core archive is "fundamentally flawed," because it does not include pre-existing HNO3 in the stratosphere. We show that they exaggerate both the enhancement predicted by our findings and pre-industrial HNO3 levels in their model, and fail to prove this assertion. Our feasibility study matched expected SPE nitrate production with ground truth measurements. It is not clear that their approach is more realistic and absence of a detailed mechanism does not disprove our results. Models can be no better than the information they are provided and in this case there continue to be significant unknowns and uncertainties, especially in the role of polar stratospheric clouds (PSCs) and possible interactions with cosmic rays that constitute lower boundary conditions. Duderstadt et al. [2014; 2016a] used incomplete, poorly-constrained and incorrect initial and boundary conditions, and they continue to advocate on the basis of uncertain results. Meanwhile, Smart et al. [2014] identified a series of ice core nitrate spikes that have since been confirmed in 10Be by McCracken and Beer [2015]. Melott et al. [2016] computationally reproduced the ionization profile of the only major balloon measurements to date. We show that our calculated nitrate enhancement is consistent with measured results, given current levels of uncertainty, and that extreme SPEs can potentially produce occasional nitrate spikes with hundreds of percent increases. Instead of repeating old arguments to dismiss nitrates as proxies of SPEs, it is past time for a dedicated, fine-resolution, multi-parameter, replicate ice core field campaign to resolve this debate. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1606.08792v1-abstract-full').style.display = 'none'; document.getElementById('1606.08792v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 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">Invited reply, submitted to JGR-Atmospheres</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1605.04926">arXiv:1605.04926</a> <span> [<a href="https://arxiv.org/pdf/1605.04926">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link 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="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/10.3847/2041-8205/826/1/L3">10.3847/2041-8205/826/1/L3 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Terrestrial Effects Of Nearby Supernovae In The Early Pleistocene </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Engler%2C+E+E">E. E. Engler</a>, <a href="/search/physics?searchtype=author&query=Kachelrie%C3%9F%2C+M">M. Kachelrie脽</a>, <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">A. L. Melott</a>, <a href="/search/physics?searchtype=author&query=Overholt%2C+A+C">A. C. Overholt</a>, <a href="/search/physics?searchtype=author&query=Semikoz%2C+D+V">D. V. Semikoz</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="1605.04926v2-abstract-short" style="display: inline;"> Recent results have strongly confirmed that multiple supernovae happened at distances ~100 pc consisting of two main events: one at 1.7 to 3.2 million years ago, and the other at 6.5 to 8.7 million years ago. These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing 60Fe on Earth and the Moon. Other events are indicated by effects in the loca… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.04926v2-abstract-full').style.display = 'inline'; document.getElementById('1605.04926v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1605.04926v2-abstract-full" style="display: none;"> Recent results have strongly confirmed that multiple supernovae happened at distances ~100 pc consisting of two main events: one at 1.7 to 3.2 million years ago, and the other at 6.5 to 8.7 million years ago. These events are said to be responsible for excavating the Local Bubble in the interstellar medium and depositing 60Fe on Earth and the Moon. Other events are indicated by effects in the local cosmic ray (CR) spectrum. Given this updated and refined picture, we ask whether such supernovae are expected to have had substantial effects on the terrestrial atmosphere and biota. In a first cut at the most probable cases, combining photon and cosmic ray effects, we find that a supernova at 100 pc can have only a small effect on terrestrial organisms from visible light and that chemical changes such as ozone depletion are weak. However, tropospheric ionization right down to the ground due to the penetration of $\geq$TeV cosmic rays will increase by nearly an order of magnitude for thousands of years, and irradiation by muons on the ground and in the upper ocean will increase 20-fold, which will approximately triple the overall radiation load on terrestrial organisms. Such irradiation has been linked to possible changes in climate and increased cancer and mutation rates. This may be related to a minor mass extinction around the Pliocene-Pleistocene boundary, and further research on the effects is needed. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1605.04926v2-abstract-full').style.display = 'none'; document.getElementById('1605.04926v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 28 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 16 May, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> May 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">Revised version accepted at ApJL</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> The Astrophysical Journal Letters, Volume 826, Number 1, 2016 </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.01816">arXiv:1604.01816</a> <span> [<a href="https://arxiv.org/pdf/1604.01816">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="High Energy Astrophysical Phenomena">astro-ph.HE</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Populations and Evolution">q-bio.PE</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/10.1089/ast.2015.1360">10.1089/ast.2015.1360 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Solar irradiance changes and phytoplankton productivity in Earth's ocean following astrophysical ionizing radiation events </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Neale%2C+P+J">Patrick J. Neale</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</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="1604.01816v1-abstract-short" style="display: inline;"> Two atmospheric responses to simulated astrophysical ionizing radiation events significant to life on Earth are production of odd-nitrogen species, especially NO2, and subsequent depletion of stratospheric ozone. Ozone depletion increases incident short-wavelength ultraviolet radiation (UVB, 280-315 nm) and longer ( > 600 nm) wavelengths of photosynthetically available radiation (PAR, 400 -700 nm)… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.01816v1-abstract-full').style.display = 'inline'; document.getElementById('1604.01816v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.01816v1-abstract-full" style="display: none;"> Two atmospheric responses to simulated astrophysical ionizing radiation events significant to life on Earth are production of odd-nitrogen species, especially NO2, and subsequent depletion of stratospheric ozone. Ozone depletion increases incident short-wavelength ultraviolet radiation (UVB, 280-315 nm) and longer ( > 600 nm) wavelengths of photosynthetically available radiation (PAR, 400 -700 nm). On the other hand, the NO2 haze decreases atmospheric transmission in the long-wavelength UVA (315-400 nm) and short wavelength PAR. Here we use the results of previous simulations of incident spectral irradiance following an ionizing radiation event to predict changes in Terran productivity focusing on photosynthesis of marine phytoplankton. The prediction is based on a spectral model of photosynthetic response developed for the dominant genera in central regions of the ocean (Synechococcus and Prochlorococcus), and remote-sensing based observations of spectral water transparency, temperature, wind speed and mixed layer depth. Predicted productivity declined after a simulated ionizing event, but the effect integrated over the water column was small. For integrations taking into account the full depth range of PAR transmission (down to 0.1% of utilizable PAR), the decrease was at most 2-3% (depending on strain), with larger effects (5-7%) for integrations just to the depth of the surface mixed layer. The deeper integrations were most affected by the decreased utilizable PAR at depth due to the NO2 haze, whereas shallower integrations were most affected by the increased surface UV. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.01816v1-abstract-full').style.display = 'none'; document.getElementById('1604.01816v1-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 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">in Astrobiology, Vol. 16, Num. 4, 2016</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1604.00344">arXiv:1604.00344</a> <span> [<a href="https://arxiv.org/pdf/1604.00344">pdf</a>, <a href="https://arxiv.org/ps/1604.00344">ps</a>, <a href="https://arxiv.org/format/1604.00344">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Plasma Physics">physics.plasm-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/10.1088/0741-3335/58/10/105008">10.1088/0741-3335/58/10/105008 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Influence of plasma turbulence on microwave propagation </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=K%C3%B6hn%2C+A">Alf K枚hn</a>, <a href="/search/physics?searchtype=author&query=Holzhauer%2C+E">Eberhard Holzhauer</a>, <a href="/search/physics?searchtype=author&query=Leddy%2C+J">Jarrod Leddy</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+M+B">Matthew B Thomas</a>, <a href="/search/physics?searchtype=author&query=Vann%2C+R+G+L">Roddy G L Vann</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="1604.00344v2-abstract-short" style="display: inline;"> It is not fully understood how electromagnetic waves propagate through plasma density fluctuations when the size of the fluctuations is comparable with the wavelength of the incident radiation. In this paper, the perturbing effect of a turbulent plasma density layer on a traversing microwave beam is simulated with full-wave simulations. The deterioration of the microwave beam is calculated as a fu… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.00344v2-abstract-full').style.display = 'inline'; document.getElementById('1604.00344v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1604.00344v2-abstract-full" style="display: none;"> It is not fully understood how electromagnetic waves propagate through plasma density fluctuations when the size of the fluctuations is comparable with the wavelength of the incident radiation. In this paper, the perturbing effect of a turbulent plasma density layer on a traversing microwave beam is simulated with full-wave simulations. The deterioration of the microwave beam is calculated as a function of the characteristic turbulence structure size, the turbulence amplitude, the depth of the interaction zone and the size of the waist of the incident beam. The maximum scattering is observed for a structure size on the order of half the vacuum wavelength. The scattering and beam broadening was found to increase linearly with the depth of the turbulence layer and quadratically with the fluctuation strength. Consequences for experiments and 3D effects are considered. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1604.00344v2-abstract-full').style.display = 'none'; document.getElementById('1604.00344v2-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 1 June, 2016; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 1 April, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> April 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">16 pages, 13 figures. This is an author-created, un-copyedited version of an article submitted for publication in Plasma Physics and Controlled Fusion. IoP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it</span> </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1602.08462">arXiv:1602.08462</a> <span> [<a href="https://arxiv.org/pdf/1602.08462">pdf</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Earth and Planetary Astrophysics">astro-ph.EP</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="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="Geophysics">physics.geo-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/10.1002/2015JD024064">10.1002/2015JD024064 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Atmospheric ionization by high-fluence, hard spectrum solar proton events and their probable appearance in the ice core archive </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Laird%2C+C+M">Claude M. Laird</a>, <a href="/search/physics?searchtype=author&query=Neuenswander%2C+B">Ben Neuenswander</a>, <a href="/search/physics?searchtype=author&query=Atri%2C+D">Dimitra Atri</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="1602.08462v1-abstract-short" style="display: inline;"> Solar energetic particles ionize the atmosphere, leading to production of nitrogen oxides. It has been suggested that some such events are visible as layers of nitrate in ice cores, yielding archives of energetic, high fluence solar proton events (SPEs). There has been controversy, due to slowness of transport for these species down from the upper stratosphere; past numerical simulations based on… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08462v1-abstract-full').style.display = 'inline'; document.getElementById('1602.08462v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1602.08462v1-abstract-full" style="display: none;"> Solar energetic particles ionize the atmosphere, leading to production of nitrogen oxides. It has been suggested that some such events are visible as layers of nitrate in ice cores, yielding archives of energetic, high fluence solar proton events (SPEs). There has been controversy, due to slowness of transport for these species down from the upper stratosphere; past numerical simulations based on an analytic calculation have shown very little ionization below the mid stratosphere. These simulations suffer from deficiencies: they consider only soft SPEs and narrow energy ranges; spectral fits are poorly chosen; with few exceptions secondary particles in air showers are ignored. Using improved simulations that follow development of the proton-induced air shower, we find consistency with recent experiments showing substantial excess ionization down to 5 km. We compute nitrate available from the 23 February 1956 SPE, which had a high fluence, hard spectrum, and well-resolved associated nitrate peak in a Greenland ice core. For the first time, we find this event can account for ice core data with timely (~ 2 months) transport downward between 46 km and the surface, thus indicating an archive of high fluence, hard spectrum SPE covering the last several millennia. We discuss interpretations of this result, as well as the lack of a clearly-defined nitrate spike associated with the soft-spectrum 3-4 August 1972 SPE. We suggest that hard-spectrum SPEs, especially in the 6 months of polar winter, are detectable in ice cores, and that more work needs to be done to investigate this. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1602.08462v1-abstract-full').style.display = 'none'; document.getElementById('1602.08462v1-abstract-short').style.display = 'inline';">△ Less</a> </span> </p> <p class="is-size-7"><span class="has-text-black-bis has-text-weight-semibold">Submitted</span> 26 February, 2016; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 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">JGR Atmospheres, in press</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> JGR Atmospheres 121 (2016) </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1512.01886">arXiv:1512.01886</a> <span> [<a href="https://arxiv.org/pdf/1512.01886">pdf</a>, <a href="https://arxiv.org/format/1512.01886">other</a>] </span> </p> <div class="tags is-inline-block"> <span class="tag is-small is-link tooltip is-tooltip-top" data-tooltip="Social and Information Networks">cs.SI</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Physics and Society">physics.soc-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/10.1371/journal.pone.0152624">10.1371/journal.pone.0152624 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Diffusion in Colocation Contact Networks: the Impact of Nodal Spatiotemporal Dynamics </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B">Bryce Thomas</a>, <a href="/search/physics?searchtype=author&query=Jurdak%2C+R">Raja Jurdak</a>, <a href="/search/physics?searchtype=author&query=Zhao%2C+K">Kun Zhao</a>, <a href="/search/physics?searchtype=author&query=Atkinson%2C+I">Ian Atkinson</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="1512.01886v2-abstract-short" style="display: inline;"> Temporal contact networks are studied to understand dynamic spreading phenomena such as communicable diseases or information dissemination. To establish how spatiotemporal dynamics of nodes impact spreading potential in colocation contact networks, we propose "inducement-shuffling" null models which break one or more correlations between times, locations and nodes. By reconfiguring the time and/or… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.01886v2-abstract-full').style.display = 'inline'; document.getElementById('1512.01886v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1512.01886v2-abstract-full" style="display: none;"> Temporal contact networks are studied to understand dynamic spreading phenomena such as communicable diseases or information dissemination. To establish how spatiotemporal dynamics of nodes impact spreading potential in colocation contact networks, we propose "inducement-shuffling" null models which break one or more correlations between times, locations and nodes. By reconfiguring the time and/or location of each node's presence in the network, these models induce alternative sets of colocation events giving rise to contact networks with varying spreading potential. This enables second-order causal reasoning about how correlations in nodes' spatiotemporal preferences not only lead to a given contact network but ultimately influence the network's spreading potential. We find the correlation between nodes and times to be the greatest impediment to spreading, while the correlation between times and locations slightly catalyzes spreading. Under each of the presented null models we measure both the number of contacts and infection prevalence as a function of time, with the surprising finding that the two have no direct causality. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1512.01886v2-abstract-full').style.display = 'none'; document.getElementById('1512.01886v2-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 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 December, 2015; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> December 2015. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1306.1976">arXiv:1306.1976</a> <span> [<a href="https://arxiv.org/pdf/1306.1976">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 Detectors">physics.ins-det</span> </div> </div> <p class="title is-5 mathjax"> Corrections on energy spectrum and scatterings for fast neutron radiography at NECTAR facility </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Shu-Quan%2C+L">Liu Shu-Quan</a>, <a href="/search/physics?searchtype=author&query=Thomas%2C+B">B眉cherl Thomas</a>, <a href="/search/physics?searchtype=author&query=Hang%2C+L">Li Hang</a>, <a href="/search/physics?searchtype=author&query=Yu-Bin%2C+Z">Zou Yu-Bin</a>, <a href="/search/physics?searchtype=author&query=Yuan-Rong%2C+L">Lu Yuan-Rong</a>, <a href="/search/physics?searchtype=author&query=Zhi-Yu%2C+G">Guo Zhi-Yu</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="1306.1976v1-abstract-short" style="display: inline;"> Neutron spectrum and scattered neutrons caused distortions are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM-II in Technische Universit盲t M眉nchen (TUM), Germany. The NECTAR… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.1976v1-abstract-full').style.display = 'inline'; document.getElementById('1306.1976v1-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1306.1976v1-abstract-full" style="display: none;"> Neutron spectrum and scattered neutrons caused distortions are major problems in fast neutron radiography and should be considered for improving the image quality. This paper puts emphasis on the removal of these image distortions and deviations for fast neutron radiography performed at the NECTAR facility of the research reactor FRM-II in Technische Universit盲t M眉nchen (TUM), Germany. The NECTAR energy spectrum is analyzed and established to modify the influence caused by neutron spectrum, as well as the Point Scattered Function (PScF) simulated by the Monte-Carlo program MCNPX is used to evaluate scattering effects from the object and improve images qualities. Good analysis results prove the sounded effects of above two corrections. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1306.1976v1-abstract-full').style.display = 'none'; document.getElementById('1306.1976v1-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, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> June 2013. </p> </li> <li class="arxiv-result"> <div class="is-marginless"> <p class="list-title is-inline-block"><a href="https://arxiv.org/abs/1302.1501">arXiv:1302.1501</a> <span> [<a href="https://arxiv.org/pdf/1302.1501">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="Atmospheric and Oceanic Physics">physics.ao-ph</span> <span class="tag is-small is-grey tooltip is-tooltip-top" data-tooltip="Geophysics">physics.geo-ph</span> <span class="tag is-small is-grey 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="Populations and Evolution">q-bio.PE</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/10.1002/grl.50222">10.1002/grl.50222 <i class="fa fa-external-link" aria-hidden="true"></i></a></span> </div> </div> </div> <p class="title is-5 mathjax"> Terrestrial effects of possible astrophysical sources of an AD 774-775 increase in 14C production </p> <p class="authors"> <span class="search-hit">Authors:</span> <a href="/search/physics?searchtype=author&query=Thomas%2C+B+C">Brian C. Thomas</a>, <a href="/search/physics?searchtype=author&query=Melott%2C+A+L">Adrian L. Melott</a>, <a href="/search/physics?searchtype=author&query=Arkenberg%2C+K+R">Keith R. Arkenberg</a>, <a href="/search/physics?searchtype=author&query=Snyder%2C+B+R">Brock R. Snyder II</a> </p> <p class="abstract mathjax"> <span class="has-text-black-bis has-text-weight-semibold">Abstract</span>: <span class="abstract-short has-text-grey-dark mathjax" id="1302.1501v2-abstract-short" style="display: inline;"> We examine possible sources of a substantial increase in tree ring 14C measurements for the years AD 774-775. Contrary to claims regarding a coronal mass ejection (CME), the required CME energy is not several orders of magnitude greater than known solar events. We consider solar proton events (SPEs) with three different fluences and two different spectra. The data may be explained by an event with… <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.1501v2-abstract-full').style.display = 'inline'; document.getElementById('1302.1501v2-abstract-short').style.display = 'none';">▽ More</a> </span> <span class="abstract-full has-text-grey-dark mathjax" id="1302.1501v2-abstract-full" style="display: none;"> We examine possible sources of a substantial increase in tree ring 14C measurements for the years AD 774-775. Contrary to claims regarding a coronal mass ejection (CME), the required CME energy is not several orders of magnitude greater than known solar events. We consider solar proton events (SPEs) with three different fluences and two different spectra. The data may be explained by an event with fluence about one order of magnitude beyond the October 1989 SPE. Two hard spectrum cases considered here result in moderate ozone depletion, so no mass extinction is implied, though we do predict increases in erythema and damage to plants from enhanced solar UV. We are able to rule out an event with a very soft spectrum that causes severe ozone depletion and subsequent biological impacts. Nitrate enhancements are consistent with their apparent absence in ice core data. The modern technological implications of such an event may be extreme, and considering recent confirmation of superflares on solar-type stars, this issue merits attention. <a class="is-size-7" style="white-space: nowrap;" onclick="document.getElementById('1302.1501v2-abstract-full').style.display = 'none'; document.getElementById('1302.1501v2-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 February, 2013; <span class="has-text-black-bis has-text-weight-semibold">v1</span> submitted 6 February, 2013; <span class="has-text-black-bis has-text-weight-semibold">originally announced</span> February 2013. </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">In press at Geophysical Research Letters</span> </p> <p class="comments is-size-7"> <span class="has-text-black-bis has-text-weight-semibold">Journal ref:</span> Geophysical Research Letters, vol. 40, 1237-1240, 2013 </p> </li> </ol> <nav class="pagination is-small is-centered breathe-horizontal" role="navigation" aria-label="pagination"> <a href="" class="pagination-previous is-invisible">Previous </a> <a href="/search/?searchtype=author&query=Thomas%2C+B&start=50" class="pagination-next" >Next </a> <ul class="pagination-list"> <li> <a href="/search/?searchtype=author&query=Thomas%2C+B&start=0" class="pagination-link is-current" aria-label="Goto page 1">1 </a> </li> <li> <a href="/search/?searchtype=author&query=Thomas%2C+B&start=50" class="pagination-link " aria-label="Page 2" aria-current="page">2 </a> </li> </ul> </nav> <div class="is-hidden-tablet">  <span class="help" style="display: inline-block;"><a href="https://github.com/arXiv/arxiv-search/releases">Search v0.5.6 released 2020-02-24</a>  </span> </div> </div> </main> <footer> <div class="columns is-desktop" role="navigation" 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