Double-coronal X-Ray and Microwave Sources Associated with a Magnetic Breakout Solar Eruption
Double-coronal X-Ray and Microwave Sources Associated with a Magnetic Breakout Solar Eruption
复制标题
与磁爆发太阳喷发相关的双日冕 X 射线和微波源
DOI：
10.3847/1538-4357/aa7462
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发表时间：
2017-07-01
影响因子：
4.9
通讯作者：
Du, Guohui
中科院分区：
文献类型：
--
作者：
Chen, Yao;Wu, Zhao;Du, Guohui
双冕硬X射线源被认为是太阳耀斑中大尺度电流片中通过磁重联进行双向能量释放的关键观测证据。在这里，我们介绍了在HXR和微波区域中观察到的双冕源的研究，揭示了不同于先前报告的新特征。这次事件与一次脚点掩埋的X1.3级耀斑(2014年4月25日，开始于世界标准时间0时17分)和一次日冕物质抛射有关，这可能是由磁场爆发过程引发的，下部源从部分隐藏的耀斑环顶向上延伸，上部源与快速挤压的旁瓣(两侧速度为∼250公里S−1)同时发生。在高达70-100keV的能量下，可以识别出高能量的上源。X射线上源的特征是通量曲线不同于下源，20keV以上的投影质心高度对能量的依赖性较弱，持续时间较短，HXR光子谱比下源略硬。此外，34 GHz的微波发射也表现出类似的双源结构，两个源的微波光谱与非热高能电子的回旋同步辐射是一致的。这些观测，特别是旁瓣和上源的快速挤入运动的同时，表明上源与拱门的这种快速运动有关(并且可能是由这种快速运动引起的)。这为在HXR和微波中观察到的日冕双源结构的起源提供了新的线索。
Double-coronal hard X-ray (HXR) sources are believed to be critical observational evidence of bi-directional energy release through magnetic reconnection in large-scale current sheets in solar flares. Here, we present a study on double-coronal sources observed in both HXR and microwave regimes, revealing new characteristics distinct from earlier reports. This event is associated with a footpoint-occulted X1.3-class flare (2014 April 25, starting at 00:17 UT) and a coronal mass ejection that were likely triggered by the magnetic breakout process, with the lower source extending upward from the top of the partially occulted flare loops and the upper source co-incident with rapidly squeezing-in side lobes (at a speed of ∼250 km s−1 on both sides). The upper source can be identified at energies as high as 70–100 keV. The X-ray upper source is characterized by flux curves that differ from those of the lower source, a weak energy dependence of projected centroid altitude above 20 keV, a shorter duration, and an HXR photon spectrum slightly harder than those of the lower source. In addition, the microwave emission at 34 GHz also exhibits a similar double-source structure and the microwave spectra at both sources are in line with gyrosynchrotron emission given by non-thermal energetic electrons. These observations, especially the co-incidence of the very-fast squeezing-in motion of side lobes and the upper source, indicate that the upper source is associated with (and possibly caused by) this fast motion of arcades. This sheds new light on the origin of the corona double-source structure observed in both HXRs and microwaves.