Subsecond Spikes in Fermi GBM X-Ray Flux as a Probe for Solar Flare Particle Acceleration
Subsecond Spikes in Fermi GBM X-Ray Flux as a Probe for Solar Flare Particle Acceleration
复制标题
DOI：
10.3847/1538-4357/abb779
复制
发表时间：
2020-03
期刊：
影响因子：
--
通讯作者：
T. Knuth;L. Glesener
中科院分区：
文献类型：
--
作者：
T. Knuth;L. Glesener
众所周知，太阳耀斑会释放大量的能量给加速的电子。研究非热X射线通量的小时间尺度（≤2s）波动提供了探索这些加速机制的本质的机会。通过比较持续时间、能带之间的时间差以及这些尖峰的周期性与各种加速机制所要求的相关时间尺度，可以对每个机制的有效性进行测试。这项工作详细分析了费米伽玛射线暴监测器（费米GBM）数据的快速波动，从两个M9.3级太阳耀斑发生在SOL 2011 -07-30和SOL 2011 -08-04。这项研究表明，费米GBM数据的有用性，作为一种手段，检查这些小的时间尺度尖峰，并提出了一个严格的方法来识别，计数和测量这些亚秒级的X射线尖峰的时间特性。在两个耀斑检查，我们发现尖峰主要发生在60-100秒的脉冲阶段的跨度。当与X射线通量的缓慢变化的分量相比时，相对尖峰强度平均在6%和28%之间。两次耀斑的平均尖峰持续时间分别为0.49和0.38s。SOL 2011 -08-04耀斑的尖峰持续时间分布遵循指数为−1.2 ± 0.3的幂律。在确定的三个尖峰间期中，仅发现一个具有周期性，在1.7 ± 0.1 Hz频率下显示出显著功率。
Solar flares are known to release a large amount of energy into accelerating electrons. Studying small timescale (≤2s) fluctuations in nonthermal X-ray flux offers the opportunity to probe the nature of those acceleration mechanisms. By comparing the durations, differences in timing between energy bands, and the periodicity of these spikes against the relevant timescales called for by various acceleration mechanisms, a test for each mechanism’s validity can be made. This work details the analysis of fast fluctuations in Fermi Gamma-ray Burst Monitor (Fermi GBM) data from two M9.3 class solar flares that occurred on SOL2011-07-30 and SOL2011-08-04. This study shows the usefulness of Fermi GBM data as a means of examining these small timescale spikes and presents a rigorous method of identifying, counting, and measuring the temporal properties of these subsecond X-ray spikes. In the two flares examined we found spikes to primarily occur in spans of 60–100 s in the impulsive phase. The relative spike intensity averaged between 6% and 28% when compared to the slowly varying component of the X-ray flux. The average spike durations were 0.49 and 0.38 s for the 2 flares. The spike duration distribution for the SOL2011-08-04 flare was found to follow a power law with a −1.2 ± 0.3 index. Of the three spiking intervals identified, only one was found to have a periodicity, showing significant power at the 1.7 ± 0.1 Hz frequency.