Energetic Electron Distribution of the Coronal Acceleration Region: First Results from Joint Microwave and Hard X-Ray Imaging Spectroscopy
Energetic Electron Distribution of the Coronal Acceleration Region: First Results from Joint Microwave and Hard X-Ray Imaging Spectroscopy
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DOI：
10.3847/2041-8213/abe471
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发表时间：
2021-02-01
影响因子：
7.9
通讯作者：
Glesener, Lindsay
中科院分区：
文献类型：
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作者：
Chen, Bin;Battaglia, Marina;Glesener, Lindsay
位于明亮耀斑弧顶上方的非热源，被称为“环顶上方”源，通常被认为是主要太阳耀斑中的主要电子加速点。2017年9月10日的X8.2临边耀斑具有这样一个环顶以上的源，它分别由扩展欧文斯谷太阳能阵列和拉马蒂高能太阳光谱成像仪在微波和硬X射线（HXR）中观测到。通过将微波和HXR成像光谱观测与多滤波器极紫外和软X射线成像数据相结合，我们推导出了该源在6.0至6.0的宽能量范围内的日冕磁场和高能电子分布。时间分辨分析表明，以上的断裂能量的电子分布迅速硬化的光谱指数从>20下降到类似于6.0在20秒内，或小于类似于10阿尔芬交叉时间的源。这些结果提供了强有力的支持以上的环顶源的主要网站，在那里正在进行的大量加速的高能电子发生在耀斑能量释放非常早。
Nonthermal sources located above bright flare arcades, referred to as the "above-the-loop-top" sources, have been often suggested as the primary electron acceleration site in major solar flares. The X8.2 limb flare on 2017 September 10 features such an above-the-loop-top source, which was observed in both microwaves and hard X-rays (HXRs) by the Expanded Owens Valley Solar Array and the Reuven Ramaty High Energy Solar Spectroscopic Imager, respectively. By combining the microwave and HXR imaging spectroscopy observations with multifilter extreme ultraviolet and soft X-ray imaging data, we derive the coronal magnetic field and energetic electron distribution of the source over a broad energy range from 6.0. Temporally resolved analysis suggests that the electron distribution above the break energy rapidly hardens with the spectral index decreasing from >20 to similar to 6.0 within 20 s, or less than similar to 10 Alfven crossing times in the source. These results provide strong support for the above-the-loop-top source as the primary site where an ongoing bulk acceleration of energetic electrons is taking place very early in the flare energy release.