Reconnection in the Post-impulsive Phase of Solar Flares
Reconnection in the Post-impulsive Phase of Solar Flares
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DOI：
10.3847/1538-4357/aabad4
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发表时间：
2018-04
期刊：
影响因子：
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通讯作者：
T. Forbes;D. Seaton;K. Reeves
中科院分区：
文献类型：
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作者：
T. Forbes;D. Seaton;K. Reeves
使用最近开发的分析程序，我们确定的“标准”模型的爆发性太阳耀斑的磁重联率。在晚期阶段，中性线位于重联电流片的下尖附近，电流片的上部区域分叉成一对Petschek型激波。尽管存在这些冲击，但如果电阻率是均匀的且流动是层流，则重新连接速率仍然很慢。只有当有一些额外的机制可以缩短中性线处扩散区的长度时，才能实现快速重连。在日出星上用X射线望远镜对等离子体流的观测表明，扩散区实际上相当短。减小扩散区长度的两种可能机制是局部电阻率和MHD湍流。
Using a recently developed analytical procedure, we determine the rate of magnetic reconnection in the “standard” model of eruptive solar flares. During the late phase, the neutral line is located near the lower tip of the reconnection current sheet, and the upper region of the current sheet is bifurcated into a pair of Petschek-type shocks. Despite the presence of these shocks, the reconnection rate remains slow if the resistivity is uniform and the flow is laminar. Fast reconnection is achieved only if there is some additional mechanism that can shorten the length of the diffusion region at the neutral line. Observations of plasma flows by the X-ray telescope on Hinode imply that the diffusion region is, in fact, quite short. Two possible mechanisms for reducing the length of the diffusion region are localized resistivity and MHD turbulence.