Connecting solar flare hard X-ray spectra to in situ electron spectra: A comparison of RHESSI and STEREO/SEPT observations
Connecting solar flare hard X-ray spectra to in situ electron spectra: A comparison of RHESSI and STEREO/SEPT observations
复制标题
将太阳耀斑硬 X 射线光谱与原位电子光谱联系起来：RHESSI 和 STEREO/SEPT 观测结果的比较
DOI：
10.1051/0004-6361/202141365
复制
发表时间：
2021
影响因子：
6.5
通讯作者：
Brüdern, M.
中科院分区：
文献类型：
--
作者：
Dresing, N.;Warmuth, A.;Effenberger, F.;Klein, K.-L.;Musset, S.;Glesener, L.;Brüdern, M.
AimsWe的目标是约束耀斑加速高能电子的加速，注入和运输过程，通过比较它们的特性在太阳与那些注入行星际spaces.MethodsWe已经确定了17个高能电子事件以及观测与SEPT仪器登上STEREO这表明一个明确的关联与硬X射线（HXR）耀斑观测与RHESSI航天器。我们比较的RHESSI HXR谱的谱指数与行星际电子。由于频繁的双幂律形状的原位电子光谱，我们特别注意的光谱指数的选择用于comparation.ResultsThe之间的时间差的电子onsets和相关的III型和微波爆发表明，电子事件被检测到在1 Au与明显的延迟范围从9到41分钟。此外，这些事件与极紫外线喷流也有很高的相关性，大多数研究的事件在时间上与日冕物质抛射相吻合。尽管观察到的发病延迟和CME的存在下，在低日冕，我们发现一个显着的相关性约0.8之间的光谱指数的HXR耀斑和原位电子。如果只考虑具有显著各向异性的事件，则相关性增加。这表明，运输效应可以改变注入光谱导致强烈减少的印记耀斑acceleration.ConclusionsWe的结论是，行星际运输效应时，必须考虑到推断太阳高能电子事件的初始加速。虽然我们的研究结果表明，一个清晰的印记耀斑加速分析的事件样本，二次加速可能存在，这可以解释所观察到的延迟。然而，有限的和可变的俯仰角覆盖的SEPT也可能是观察到的延迟的原因。
AimsWe aim to constrain the acceleration, injection, and transport processes of flare-accelerated energetic electrons by comparing their characteristics at the Sun with those injected into interplanetary space.MethodsWe have identified 17 energetic electron events well-observed with the SEPT instrument aboard STEREO which show a clear association with a hard X-ray (HXR) flare observed with the RHESSI spacecraft. We compare the spectral indices of the RHESSI HXR spectra with those of the interplanetary electrons. Because of the frequent double-power-law shape of the in situ electron spectra, we paid special attention to the choice of the spectral index used for comparison.ResultsThe time difference between the electron onsets and the associated type III and microwave bursts suggests that the electron events are detected at 1 AU with apparent delays ranging from 9 to 41 min. While the parent solar activity is clearly impulsive, also showing a high correlation with extreme ultraviolet jets, most of the studied events occur in temporal coincidence with coronal mass ejections (CMEs). In spite of the observed onset delays and presence of CMEs in the low corona, we find a significant correlation of about 0.8 between the spectral indices of the HXR flare and the in situ electrons. The correlations increase if only events with significant anisotropy are considered. This suggests that transport effects can alter the injected spectra leading to a strongly reduced imprint of the flare acceleration.ConclusionsWe conclude that interplanetary transport effects must be taken into account when inferring the initial acceleration of solar energetic electron events. Although our results suggest a clear imprint of flare acceleration for the analyzed event sample, a secondary acceleration might be present which could account for the observed delays. However, the limited and variable pitch-angle coverage of SEPT could also be the reason for the observed delays.