What aspects of solar flares can be clarified with mm/submm observations?
What aspects of solar flares can be clarified with mm/submm observations?
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DOI：
10.3389/fspas.2022.966444
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发表时间：
2022-09
影响因子：
5.7
通讯作者：
G. Fleishman;J. M. Martínez Oliveros;E. Landi;L. Glesener
中科院分区：
文献类型：
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作者：
G. Fleishman;J. M. Martínez Oliveros;E. Landi;L. Glesener
本文提出了关于太阳耀斑的几个尚未解决的问题，这些问题可以通过ALMA的毫米/亚毫米观测来回答或至少澄清。我们重点研究了太阳耀斑的前期阶段和起始阶段以及耀斑期间粒子加速的效率等问题。为了研究耀斑前阶段，我们建议利用ALMA的超高灵敏度和高空间分辨率，这有望以高空间分辨率识别耀斑前发射的早期增强，并将它们与潜在的光球磁结构和色球耀斑带联系起来。除了揭示耀斑的开始，这些耀斑前的测量将以多种方式帮助研究粒子加速。高频成像光谱数据与微波数据相结合，将允许量化非热电子能谱中的高能截止，从而有助于限制加速效率。利用成像偏振数据检测和量化次级相对论性正电子（由非热加速离子产生）的贡献将有助于约束耀斑中非热核的加速效率。以高空间分辨率探测到“神秘的”上升光谱成分将有助于确定该成分的发射机制，并将有助于量化燃烧等离子体的非热或热成分。我们讨论了什么样的ALMA观测模式最适合处理这些目标。
This paper identifies several unsolved questions about solar flares, which can potentially be answered or at least clarified with mm/submm observations with ALMA. We focus on such questions as preflare phases and the initiation of solar flares and the efficiency of particle acceleration during flares. To investigate the preflare phase we propose to use the extraordinary sensitivity and high spatial resolution of ALMA, which promises to identify very early enhancements of preflare emission with high spatial resolution and link them to the underlying photospheric magnetic structure and chromospheric flare ribbons. In addition to revealing the flare onsets, these preflare measurements will aid in the investigation of particle acceleration in multiple ways. High-frequency imaging spectroscopy data in combination with the microwave data will permit the quantification of the high-energy cutoff in the nonthermal electron spectra, thus helping to constrain the acceleration efficiency. Detection and quantification of secondary relativistic positron (produced due to nonthermal accelerated ions) contribution using the imaging polarimetry data will help constrain acceleration efficiency of nonthermal nuclei in flares. Detection of a “mysterious” rising spectral component with high spatial resolution will help determine the emission mechanism responsible for this component, and will then help in quantifying this either nonthermal or thermal component of the flaring plasma. We discuss what ALMA observing mode(s) would be the most suitable for addressing these objectives.