Pub Date : 2024-04-12DOI: 10.3389/fspas.2024.1320809
Simon Wing, J. Berchem, C. Escoubet, Charles Farrugia
The dayside particle precipitation during the passage of a solar wind rotational discontinuity (RD) event on 10 April 2015 is examined and reviewed. The RD leads to complex structures at the magnetopause, boundary layer, mantle, and cusp even though the geomagnetic activity level remains low. Particle precipitation data from DMSP F17 reveal the formation of an unusual boundary layer where the low energy (cold) ions exhibit energy-latitude dispersion that is usually associated with mantle while the high energy (hot) ions look like typical magnetospheric ions. DMSP F17 and F19 observe a double cusp that is a signature of magnetic reconnection occurring at both high- and low-latitudes due to the dominant IMF By. A global MHD simulation of the event supports the existence of the simultaneous reconnections at high- and low-latitude magnetopause that are consistent with the anti-parallel and component merging models, respectively. Finally, Cluster C2, located at high-latitude and high-altitude in the southern hemisphere, observes velocity fluctuations and reversals with peak-to-peak amplitudes >800 km·s–1 as it crosses the magnetopause. Guided by the MHD simulation, the Cluster observation can be interpreted as the spacecraft crossing reconnection outflows while moving from one side of the X-line to the other.
本文对2015年4月10日太阳风旋转不连续（RD）事件期间的日侧粒子沉降进行了研究和回顾。尽管地磁活动水平仍然很低，但旋转不连续事件导致磁极面、边界层、地幔和尖顶的复杂结构。来自 DMSP F17 的粒子析出数据揭示了不寻常边界层的形成，其中低能量（冷）离子表现出通常与地幔相关的能量纬度分散，而高能量（热）离子则看起来像典型的磁层离子。DMSP F17 和 F19 观测到一个双尖顶，这是由于主导的 IMF By 在高纬度和低纬度都发生磁再连接的标志。对这一事件的全球 MHD 模拟支持在高纬度和低纬度磁层顶同时发生的再连接，这分别与反平行模型和分量合并模型相一致。最后，位于南半球高纬度和高海拔地区的 C2 星团在穿越磁层顶时观测到了峰-峰振幅大于 800 km-s-1 的速度波动和反转。在 MHD 模拟的指导下，Cluster 的观测结果可以解释为航天器在从 X 线一侧移动到另一侧时穿过了再连接外流。
{"title":"Complex dayside particle precipitation observed during the passage of a solar wind rotational discontinuity","authors":"Simon Wing, J. Berchem, C. Escoubet, Charles Farrugia","doi":"10.3389/fspas.2024.1320809","DOIUrl":"https://doi.org/10.3389/fspas.2024.1320809","url":null,"abstract":"The dayside particle precipitation during the passage of a solar wind rotational discontinuity (RD) event on 10 April 2015 is examined and reviewed. The RD leads to complex structures at the magnetopause, boundary layer, mantle, and cusp even though the geomagnetic activity level remains low. Particle precipitation data from DMSP F17 reveal the formation of an unusual boundary layer where the low energy (cold) ions exhibit energy-latitude dispersion that is usually associated with mantle while the high energy (hot) ions look like typical magnetospheric ions. DMSP F17 and F19 observe a double cusp that is a signature of magnetic reconnection occurring at both high- and low-latitudes due to the dominant IMF By. A global MHD simulation of the event supports the existence of the simultaneous reconnections at high- and low-latitude magnetopause that are consistent with the anti-parallel and component merging models, respectively. Finally, Cluster C2, located at high-latitude and high-altitude in the southern hemisphere, observes velocity fluctuations and reversals with peak-to-peak amplitudes >800 km·s–1 as it crosses the magnetopause. Guided by the MHD simulation, the Cluster observation can be interpreted as the spacecraft crossing reconnection outflows while moving from one side of the X-line to the other.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-04-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140708852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.3389/fspas.2024.1391070
Xu Du, Hai-long Zhang, Shao-Cong Guo, Ya-Zhou Zhang, Jian Li, Jie Wang, X. Ye, Han Wu, Ting Zhang
In order to realize the real-time processing and analysis of astronomical ultra-wide bandwidth signals, this study proposes a sub-band division algorithm based on RFSoC. The algorithm uses Kaiser window to design FIR prototype low-pass filter, adopts critical sampling polyphase filter bank to decompose ultra-wide bandwidth signal into several sub-bands, and encapsulates each sub-band into VDIF data frame and sends it to GPU server. The algorithm is implemented on RFSoC platform, and its effectiveness is verified by simulation and actual observation. The experimental results show that the algorithm can divide the astronomical ultra-wide bandwidth signal into multiple sub-bands in real time, packetize and transmit them to GPU. This research provides reproducible design and project for ultra-wide bandwidth signal sub-band division with low spectrum leakage and aliasing, high data accuracy, and fast processing speed.
为了实现对天文超宽带信号的实时处理和分析，本研究提出了一种基于 RFSoC 的子带划分算法。该算法利用 Kaiser 窗口设计 FIR 原型低通滤波器，采用临界采样多相滤波器组将超宽带信号分解为多个子带，并将每个子带封装为 VDIF 数据帧发送至 GPU 服务器。该算法在 RFSoC 平台上实现，并通过仿真和实际观测验证了其有效性。实验结果表明，该算法能将天文超宽带信号实时划分为多个子波段，并打包发送给 GPU。该研究为超宽带信号子波段划分提供了可重复的设计和项目，具有频谱泄漏和混叠少、数据精度高、处理速度快等特点。
{"title":"A sub-band division algorithm for ultra-wide bandwidth pulsar signals based on RFSoC","authors":"Xu Du, Hai-long Zhang, Shao-Cong Guo, Ya-Zhou Zhang, Jian Li, Jie Wang, X. Ye, Han Wu, Ting Zhang","doi":"10.3389/fspas.2024.1391070","DOIUrl":"https://doi.org/10.3389/fspas.2024.1391070","url":null,"abstract":"In order to realize the real-time processing and analysis of astronomical ultra-wide bandwidth signals, this study proposes a sub-band division algorithm based on RFSoC. The algorithm uses Kaiser window to design FIR prototype low-pass filter, adopts critical sampling polyphase filter bank to decompose ultra-wide bandwidth signal into several sub-bands, and encapsulates each sub-band into VDIF data frame and sends it to GPU server. The algorithm is implemented on RFSoC platform, and its effectiveness is verified by simulation and actual observation. The experimental results show that the algorithm can divide the astronomical ultra-wide bandwidth signal into multiple sub-bands in real time, packetize and transmit them to GPU. This research provides reproducible design and project for ultra-wide bandwidth signal sub-band division with low spectrum leakage and aliasing, high data accuracy, and fast processing speed.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140716750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.3389/fspas.2024.1382511
M. F. Bashir, Elena Kronberg, Lunjin Chen
{"title":"Editorial: Circulation of heavy ions and their role in regulating the near-earth plasma dynamics","authors":"M. F. Bashir, Elena Kronberg, Lunjin Chen","doi":"10.3389/fspas.2024.1382511","DOIUrl":"https://doi.org/10.3389/fspas.2024.1382511","url":null,"abstract":"","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140718562","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-10DOI: 10.3389/fspas.2024.1372057
William Bains, Sara Seager, David L. Clements, J. Greaves, Paul B Rimmer, J. Petkowski
The tentative detection of ppb levels of phosphine (PH3) in the clouds of Venus was extremely surprising, as this reduced gas was not expected to be a component of Venus’ oxidized atmosphere. Despite potential confirmation in legacy Pioneer Venus mass spectrometry data, the detection remains controversial. Here we review the potential production of phosphine by gas reactions, surface and sub-surface geochemistry, photochemistry, and other nonequilibrium processes. None of these potential phosphine production pathways is sufficient to explain the presence of phosphine in Venus atmosphere at near the observed abundance. The source of atmospheric PH3 could be unknown geo- or photochemistry, which would imply that the consensus on Venus’ chemistry is significantly incomplete. An even more extreme possibility is that a strictly aerial microbial biosphere produces PH3. The detection of phosphine adds to the complexity of chemical processes in the Venusian environment and motivates better quantitation of the gas phase chemistry of phosphorus species and in situ follow-up sampling missions to Venus.
{"title":"Source of phosphine on Venus—An unsolved problem","authors":"William Bains, Sara Seager, David L. Clements, J. Greaves, Paul B Rimmer, J. Petkowski","doi":"10.3389/fspas.2024.1372057","DOIUrl":"https://doi.org/10.3389/fspas.2024.1372057","url":null,"abstract":"The tentative detection of ppb levels of phosphine (PH3) in the clouds of Venus was extremely surprising, as this reduced gas was not expected to be a component of Venus’ oxidized atmosphere. Despite potential confirmation in legacy Pioneer Venus mass spectrometry data, the detection remains controversial. Here we review the potential production of phosphine by gas reactions, surface and sub-surface geochemistry, photochemistry, and other nonequilibrium processes. None of these potential phosphine production pathways is sufficient to explain the presence of phosphine in Venus atmosphere at near the observed abundance. The source of atmospheric PH3 could be unknown geo- or photochemistry, which would imply that the consensus on Venus’ chemistry is significantly incomplete. An even more extreme possibility is that a strictly aerial microbial biosphere produces PH3. The detection of phosphine adds to the complexity of chemical processes in the Venusian environment and motivates better quantitation of the gas phase chemistry of phosphorus species and in situ follow-up sampling missions to Venus.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140719334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-08DOI: 10.3389/fspas.2024.1391990
Daniel Weimer
{"title":"The significance of small-scale electric fields may be overestimated","authors":"Daniel Weimer","doi":"10.3389/fspas.2024.1391990","DOIUrl":"https://doi.org/10.3389/fspas.2024.1391990","url":null,"abstract":"","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140728036","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-04DOI: 10.3389/fspas.2024.1384196
Erdal Yiğit, Ayden L. S. Gann, Alexander S. Medvedev, Federico Gasperini, Qian Wu, Md. Nazmus Sakib
The response of the thermospheric daytime longitudinally averaged zonal and meridional winds and neutral temperature to the 2020/2021 major sudden stratospheric warming (SSW) is studied at low-to middle latitudes (0◦ - 40◦N) using observations by NASA’s ICON and GOLD satellites. The major SSW commenced on 1 January 2021 and lasted for several days. Results are compared with the non-SSW winter of 2019/2020 and pre-SSW period of December 2020. Major changes in winds and temperature are observed during the SSW. The northward and westward winds are enhanced in the thermosphere especially above ∼140 km during the warming event, while temperature around 150 km drops up to 50 K compared to the pre-SSW phase. Changes in the zonal and meridional winds are likely caused by the SSW-induced changes in the propagation and dissipation conditions of internal atmospheric waves. Changes in the horizontal circulation during the SSW can generate upwelling at low-latitudes, which can contribute to the adiabatic cooling of the low-latitude thermosphere. The observed changes during the major SSW are a manifestation of long-range vertical coupling in the atmosphere.
{"title":"Observation of vertical coupling during a major sudden stratospheric warming by ICON and GOLD: a case study of the 2020/2021 warming event","authors":"Erdal Yiğit, Ayden L. S. Gann, Alexander S. Medvedev, Federico Gasperini, Qian Wu, Md. Nazmus Sakib","doi":"10.3389/fspas.2024.1384196","DOIUrl":"https://doi.org/10.3389/fspas.2024.1384196","url":null,"abstract":"The response of the thermospheric daytime longitudinally averaged zonal and meridional winds and neutral temperature to the 2020/2021 major sudden stratospheric warming (SSW) is studied at low-to middle latitudes (0◦ - 40◦N) using observations by NASA’s ICON and GOLD satellites. The major SSW commenced on 1 January 2021 and lasted for several days. Results are compared with the non-SSW winter of 2019/2020 and pre-SSW period of December 2020. Major changes in winds and temperature are observed during the SSW. The northward and westward winds are enhanced in the thermosphere especially above ∼140 km during the warming event, while temperature around 150 km drops up to 50 K compared to the pre-SSW phase. Changes in the zonal and meridional winds are likely caused by the SSW-induced changes in the propagation and dissipation conditions of internal atmospheric waves. Changes in the horizontal circulation during the SSW can generate upwelling at low-latitudes, which can contribute to the adiabatic cooling of the low-latitude thermosphere. The observed changes during the major SSW are a manifestation of long-range vertical coupling in the atmosphere.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-04-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140743171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-28DOI: 10.3389/fspas.2024.1324796
J. M. Piotrowska, J. A. García, D. Walton, R. S. Beckmann, D. Stern, D. Ballantyne, D. R. Wilkins, S. Bianchi, P. Boorman, J. Buchner, C.-T. Chen, P. Coppi, T. Dauser, A. Fabian, E. Kammoun, K. Madsen, L. Mallick, G. Matt, G. Matzeu, E. Nardini, A. Pizzetti, S. Puccetti, C. Ricci, F. Tombesi, N. Torres-Albà, K.-W. Wong
Constraining the primary growth channel of supermassive black holes (SMBHs) remains one the most actively debated questions in the context of cosmological structure formation. Owing to the expected connection between SMBH spin parameter evolution and the accretion and merger history of individual black holes, population spin measurements offer a rare observational window into the cosmic growth of SMBHs. As of today, the most common method for estimating SMBH spin relies on modeling the relativistically broaden atomic profiles in the reflection spectrum observed in X-rays. In this paper, we study the observational requirements needed to confidently distinguish between the primary SMBH growth channels based on their distinct spin-mass distributions predicted by the Horizon-AGN cosmological simulation. Indoing so, we characterize outstanding limitations associated with the existing measurements and discuss the landscape of future observational campaigns which could be planned and executed with future X-ray observatories. We focus our attention on the High-Energy X-ray Probe (HEX-P), a proposed probe-class mission designed to serve the high-energy community in the 2030s.
制约超大质量黑洞（SMBHs）的主要生长通道仍然是宇宙学结构形成方面争论最激烈的问题之一。由于超大质量黑洞自旋参数演化与单个黑洞的吸积和合并历史之间的预期联系，群体自旋测量为了解超大质量黑洞的宇宙成长提供了一个难得的观测窗口。到目前为止，估算 SMBH 自旋最常用的方法是对 X 射线反射光谱中相对论拓宽的原子轮廓进行建模。在本文中，我们研究了根据 Horizon-AGN 宇宙学模拟预测的不同自旋-质量分布，有把握地区分主要 SMBH 生长通道所需的观测条件。在此过程中，我们描述了与现有测量相关的突出局限性，并讨论了未来 X 射线天文台可以计划和执行的未来观测活动的前景。我们将注意力集中在高能 X 射线探测器（HEX-P）上，这是一项拟议中的探测器级任务，旨在 2030 年代为高能界服务。
{"title":"The high energy X-ray probe (HEX-P): constraining supermassive black hole growth with population spin measurements","authors":"J. M. Piotrowska, J. A. García, D. Walton, R. S. Beckmann, D. Stern, D. Ballantyne, D. R. Wilkins, S. Bianchi, P. Boorman, J. Buchner, C.-T. Chen, P. Coppi, T. Dauser, A. Fabian, E. Kammoun, K. Madsen, L. Mallick, G. Matt, G. Matzeu, E. Nardini, A. Pizzetti, S. Puccetti, C. Ricci, F. Tombesi, N. Torres-Albà, K.-W. Wong","doi":"10.3389/fspas.2024.1324796","DOIUrl":"https://doi.org/10.3389/fspas.2024.1324796","url":null,"abstract":"Constraining the primary growth channel of supermassive black holes (SMBHs) remains one the most actively debated questions in the context of cosmological structure formation. Owing to the expected connection between SMBH spin parameter evolution and the accretion and merger history of individual black holes, population spin measurements offer a rare observational window into the cosmic growth of SMBHs. As of today, the most common method for estimating SMBH spin relies on modeling the relativistically broaden atomic profiles in the reflection spectrum observed in X-rays. In this paper, we study the observational requirements needed to confidently distinguish between the primary SMBH growth channels based on their distinct spin-mass distributions predicted by the Horizon-AGN cosmological simulation. Indoing so, we characterize outstanding limitations associated with the existing measurements and discuss the landscape of future observational campaigns which could be planned and executed with future X-ray observatories. We focus our attention on the High-Energy X-ray Probe (HEX-P), a proposed probe-class mission designed to serve the high-energy community in the 2030s.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140369009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-25DOI: 10.3389/fspas.2024.1396037
Shi-Long Liao, Zhao-Xiang Qi, Jia-Cheng Liu
{"title":"Editorial: Astrometry with the Chinese space station telescope","authors":"Shi-Long Liao, Zhao-Xiang Qi, Jia-Cheng Liu","doi":"10.3389/fspas.2024.1396037","DOIUrl":"https://doi.org/10.3389/fspas.2024.1396037","url":null,"abstract":"","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140385184","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-08DOI: 10.3389/fspas.2024.1368043
D. Reames
The acceleration and transport of solar energetic particles (SEPs) cause their abundance, measured at a constant velocity, to be enhanced or suppressed as a function of the magnetic rigidity of each ion, and hence, of its atomic mass-to-charge ratio of A/Q. Ion charges, in turn, depend upon the source electron temperature. In small “impulsive” SEP events, arising from solar jets, acceleration during magnetic reconnection causes steep power-law abundance enhancements. These impulsive SEP events can have 1,000-fold enhancements of heavy elements from sources at ∼2.5 MK and similar enhancements of 3He/4He and of streaming electrons that drive type-III radio bursts. Gamma-ray lines show that solar flares also accelerate 3He-rich ions, but their electrons and ions remain trapped in magnetic loops, so they dissipate their energy as X-rays, γ-rays, heat, and light. “Gradual” SEPs accelerated at shock waves, driven by fast coronal mass ejections (CMEs), can show power-law abundance enhancements or depressions, even with seed ions from the ambient solar corona. In addition, shocks can reaccelerate seed particles from residual impulsive SEPs with their pre-existing signature heavy-ion enhancements. Different patterns of abundance often show that heavy elements are dominated by a source different from that of H and He. Nevertheless, the SEP abundance, averaged over many large events, defines the abundance of the corona itself, which differs from the solar photosphere as a function of the first ionization potential (FIP) since ions, with FIP <10 eV, are driven upward by forces of electromagnetic waves, which neutral atoms, with FIP >10 eV, cannot feel. Thus, SEPs provide a measurement of element abundance in the solar corona, distinct from solar wind, and may even better define the photosphere for some elements.
太阳高能粒子（SEPs）的加速和传输导致其丰度（以恒定速度测量）的增强或抑制，这是每个离子的磁刚度的函数，因此也是其原子质量-电荷比 A/Q 的函数。离子电荷反过来又取决于源电子温度。在由太阳喷流引起的小型 "脉冲 "SEP 事件中，磁重联过程中的加速会导致陡峭的幂律丰度增强。这些脉冲 SEP 事件可以使来自 ∼2.5 MK 源的重元素丰度增强 1000 倍，并使 3He/4He 和驱动 III 型射电暴的流电子丰度增强类似程度。伽马射线线显示，太阳耀斑也会加速富含3He的离子，但它们的电子和离子仍然被困在磁环中，因此它们会以X射线、γ射线、热和光的形式耗散能量。在快速日冕物质抛射（CME）的驱动下，在冲击波中加速的 "渐变 "SEPs 可以显示出幂律丰度的增强或减弱，即使是来自周围日冕的种子离子也是如此。此外，冲击还能重新加速来自残余冲激式日冕物质抛射的种子粒子，其原有的特征是重离子增强。不同的丰度模式往往表明重元素的主要来源不同于 H 和 He 的来源。然而，SEP 丰度是许多大型事件的平均值，它定义了日冕本身的丰度，日冕不同于太阳光层，它是第一电离势（FIP）的函数，因为 FIP 为 10 eV 的离子无法感受到日冕。因此，SEP 可以测量日冕中不同于太阳风的元素丰度，甚至可以更好地定义某些元素的光球。
{"title":"Element abundance and the physics of solar energetic particles","authors":"D. Reames","doi":"10.3389/fspas.2024.1368043","DOIUrl":"https://doi.org/10.3389/fspas.2024.1368043","url":null,"abstract":"The acceleration and transport of solar energetic particles (SEPs) cause their abundance, measured at a constant velocity, to be enhanced or suppressed as a function of the magnetic rigidity of each ion, and hence, of its atomic mass-to-charge ratio of A/Q. Ion charges, in turn, depend upon the source electron temperature. In small “impulsive” SEP events, arising from solar jets, acceleration during magnetic reconnection causes steep power-law abundance enhancements. These impulsive SEP events can have 1,000-fold enhancements of heavy elements from sources at ∼2.5 MK and similar enhancements of 3He/4He and of streaming electrons that drive type-III radio bursts. Gamma-ray lines show that solar flares also accelerate 3He-rich ions, but their electrons and ions remain trapped in magnetic loops, so they dissipate their energy as X-rays, γ-rays, heat, and light. “Gradual” SEPs accelerated at shock waves, driven by fast coronal mass ejections (CMEs), can show power-law abundance enhancements or depressions, even with seed ions from the ambient solar corona. In addition, shocks can reaccelerate seed particles from residual impulsive SEPs with their pre-existing signature heavy-ion enhancements. Different patterns of abundance often show that heavy elements are dominated by a source different from that of H and He. Nevertheless, the SEP abundance, averaged over many large events, defines the abundance of the corona itself, which differs from the solar photosphere as a function of the first ionization potential (FIP) since ions, with FIP <10 eV, are driven upward by forces of electromagnetic waves, which neutral atoms, with FIP >10 eV, cannot feel. Thus, SEPs provide a measurement of element abundance in the solar corona, distinct from solar wind, and may even better define the photosphere for some elements.","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140077196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-03-07DOI: 10.3389/fspas.2024.1342694
Chhandak Basu, Scott M. Perl
{"title":"The use of RNA-seq for the study of physiological adaptations of halophiles in extreme environments for astrobiological data interpretation","authors":"Chhandak Basu, Scott M. Perl","doi":"10.3389/fspas.2024.1342694","DOIUrl":"https://doi.org/10.3389/fspas.2024.1342694","url":null,"abstract":"","PeriodicalId":46793,"journal":{"name":"Frontiers in Astronomy and Space Sciences","volume":null,"pages":null},"PeriodicalIF":3.0,"publicationDate":"2024-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140077671","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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