Spectropolarimetric Insight into Plasma Sheet Dynamics of a Solar Flare
Spectropolarimetric Insight into Plasma Sheet Dynamics of a Solar Flare
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DOI：
10.3847/2041-8213/ab5d34
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发表时间：
2019-12-20
影响因子：
7.9
通讯作者：
van Driel-Gesztelyi, Lidia
中科院分区：
文献类型：
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作者：
French, Ryan J.;Judge, Philip G.;van Driel-Gesztelyi, Lidia
我们检查了来自日冕多通道偏振仪(COMP)的光谱偏振数据，这些数据是在2017年9月10日X8.2太阳耀斑在西太阳边缘演化期间获得的。CoMP捕获了FeXIII的两条发射线在1074.7 nm和1079.8 nm处的线偏振光，从1.03到1.5太阳半径。这里我们关注位于明亮耀斑环圈上方和日冕物质抛射之下的高温等离子体片。偏振具有显著且连贯的空间结构，与等离子体片对齐的偏振出乎意料地小。通过消除，我们发现需要小尺度的磁场结构才能引起如此显著的退极化，并认为重联过程中的等离子体形成(与撕裂模不稳定性有关)在仪器分辨率低于6 mm的尺度上产生了磁结构。我们的结论是，使用新的日冕仪进行偏振测量，如即将推出的丹尼尔·K·井上太阳望远镜，将进一步加深我们对日冕中磁场重联和湍流发展的理解。
We examine spectropolarimetric data from the Coronal Multi-channel Polarimeter (CoMP) instrument, acquired during the evolution of the 2017 September 10 X8.2 solar flare on the western solar limb. CoMP captured linearly polarized light from two emission lines of Fe XIII at 1074.7 and 1079.8 nm, from 1.03 to 1.5 solar radii. We focus here on the hot plasma sheet lying above the bright flare loops and beneath the ejected coronal mass ejection. The polarization has a striking and coherent spatial structure, with unexpectedly small polarization aligned with the plasma sheet. By elimination, we find that small-scale magnetic field structure is needed to cause such significant depolarization, and suggest that plasmoid formation during reconnection (associated with the tearing-mode instability) creates magnetic structure on scales below instrument resolution of 6 Mm. We conclude that polarization measurements with new coronagraphs, such as the upcoming Daniel K. Inouye Solar Telescope, will further enhance our understanding of magnetic reconnection and development of turbulence in the solar corona.