Broken-up spectra of the loop-top hard X-ray source during a solar limb flare
Broken-up spectra of the loop-top hard X-ray source during a solar limb flare
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太阳临边耀斑期间环顶硬 X 射线源的分解光谱
DOI：
10.1088/1674-4527/19/12/173
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发表时间：
2019-06
影响因子：
1.8
通讯作者：
Kong Xiang-Liang
中科院分区：
文献类型：
--
作者：
Ning Hao;Chen Yao;Lee Jeongwoo;Wu Zhao;Su Yang;Kong Xiang-Liang
太阳硬x射线（HXRs）以足点源或日冕源的形式出现。每个单独的源都提供了自己的非热电子加速和等离子体加热的关键信息。早期的研究发现，在一些事件中HXR发射表现为幂律谱的破碎，基于空间积分光谱分析，其破碎能量在几百keV左右，并且不区分单个源的贡献。本文报道了利用Reuven Ramaty高能太阳光谱成像仪（RHESSI）在SOL2017-09-10T16:06 （GOES X8.2级）耀斑期间记录的HXR数据研究日冕源的破裂光谱。耀斑发生在西翼的后方，其足点源大部分被圆盘遮挡。在耀斑峰值前后，我们可以清楚地识别出这种只属于日冕源的破碎光谱。由于预计这次强烈的太阳耀斑会对RHESSI光谱产生显著的堆积效应，我们选择了堆积校正因子p = 2。在这种情况下，我们发现所得的RHESSI温度（~ 30 MK）与GOES软x射线温度相似，断裂能量为45-60 keV。在断裂能量以上，随着时间的推移，光谱指数从3.4变硬到2.7，断裂能量以上和以下的光谱指数差从1.5增加到5。然而，我们注意到，当假设p = 2时，单次幂律拟合也是可能的，RHESSI温度比GOES温度高约10 MK。简要讨论了环顶HXR源的破裂光谱的可能情况。
Solar hard X-rays (HXRs) appear in the form of either footpoint sources or coronal sources. Each individual source provides its own critical information on acceleration of nonthermal electrons and plasma heating. Earlier studies found that the HXR emission in some events manifests a broken-up power-law spectrum, with the break energy around a few hundred keV based on spatially-integrated spectral analysis, and it does not distinguish the contributions from individual sources. In this paper, we report on the broken-up spectra of a coronal source studied using HXR data recorded by Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) during the SOL2017–09–10T16:06 (GOES class X8.2) flare. The flare occurred behind the western limb and its footpoint sources were mostly occulted by the disk. We could clearly identify such broken-up spectra pertaining solely to the coronal source during the flare peak time and after. Since a significant pileup effect on the RHESSI spectra is expected for this intense solar flare, we have selected the pileup correction factor, p = 2. In this case, we found the resulting RHESSI temperature (∼30 MK) to be similar to the GOES soft X-ray temperature and break energies of 45–60 keV. Above the break energy, the spectrum hardens with time from spectral index of 3.4 to 2.7, and the difference in spectral indices below and above the break energy increases from 1.5 to 5 with time. However, we note that when p = 2 is assumed, a single power-law fitting is also possible with the RHESSI temperature higher than the GOES temperature by ∼10 MK. Possible scenarios for the broken-up spectra of the loop-top HXR source are briefly discussed.
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影响因子：
2.8
作者：
W. Pesnell;B. Thompson;P. Chamberlin
通讯作者：
W. Pesnell;B. Thompson;P. Chamberlin
DOI：
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发表时间：
1964
期刊：
--
影响因子：
--
作者：
H. Carmichael
通讯作者：
H. Carmichael
DOI：
10.3847/2041-8213/aa9476
发表时间：
2017-10
期刊：
The Astrophysical Journal Letters
影响因子：
--
作者：
Shuhong Yang;Jun Zhang;Xiaoshuai Zhu;Q. Song
通讯作者：
Shuhong Yang;Jun Zhang;Xiaoshuai Zhu;Q. Song
DOI：
10.1088/0004-637x/799/2/129
发表时间：
2014-12
期刊：
The Astrophysical Journal
影响因子：
--
作者：
M. Oka;S. Krucker;H. Hudson;P. Saint-Hilaire
通讯作者：
M. Oka;S. Krucker;H. Hudson;P. Saint-Hilaire
DOI：
10.1086/164306
发表时间：
1986-06
期刊：
The Astrophysical Journal
影响因子：
--
作者：
E. Cliver;B. Dennis;A. Kiplinger;S. Kane;D. Neidig
通讯作者：
E. Cliver;B. Dennis;A. Kiplinger;S. Kane;D. Neidig