Rapid Evolution of Bald Patches in a Major Solar Eruption
Rapid Evolution of Bald Patches in a Major Solar Eruption
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DOI：
10.3847/2041-8213/ac31b7
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发表时间：
2021-10
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影响因子：
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通讯作者：
Jonathan H. Lee;Xudong Sun (孙旭东);M. Kazachenko
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文献类型：
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作者：
Jonathan H. Lee;Xudong Sun (孙旭东);M. Kazachenko
秃斑（BP）是一种磁拓扑特征，其中u形场线与光球相切。穿过BP的场线跟踪一个分离矩阵表面，在那里优先发生重连接。本文研究了ar12673在第24太阳周期最强烈的X9.3级耀斑期间多个强场bp的演化。位于最初的耀斑带之间的中央BP在35分钟内大部分“解体”。更偏远的英国南部幸存了下来。崩解表现为中剪切角旋转9°；水平场的垂直分量（相对于极性反转线）改变了符号。平行分量呈现出1 kG的阶梯式永久增加，与先前对耀斑相关的“磁印记”的观察一致。观测结果表明，大喷发期间的磁重联可能涉及整个BP分离体，导致从BP到剪切拱廊的磁拓扑变化。
A bald patch (BP) is a magnetic topological feature where U-shaped field lines turn tangent to the photosphere. Field lines threading the BP trace a separatrix surface where reconnection preferentially occurs. Here we study the evolution of multiple, strong-field BPs in AR 12673 during the most intense, X9.3 flare of solar cycle 24. The central BP, located between the initial flare ribbons, largely “disintegrated” within 35 minutes. The more remote, southern BP survived. The disintegration manifested as a 9° rotation of the median shear angle; the perpendicular component of the horizontal field (with respect to the polarity inversion line) changed sign. The parallel component exhibited a step-wise, permanent increase of 1 kG, consistent with previous observations of the flare-related “magnetic imprint.” The observations suggest that magnetic reconnection during a major eruption may involve entire BP separatrices, leading to a change of magnetic topology from BPs to sheared arcades.