Critical Issues For Understanding Particle Acceleration in Impulsive Solar Flares
Critical Issues For Understanding Particle Acceleration in Impulsive Solar Flares
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DOI：
10.1029/97ja00976
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发表时间：
1997-01
期刊：
影响因子：
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通讯作者：
James A. Miller;P. Cargill;A. Emslie;G. Holman;B. Dennis;T. N. Rosa;R. Winglee;S. G. Benka
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文献类型：
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作者：
James A. Miller;P. Cargill;A. Emslie;G. Holman;B. Dennis;T. N. Rosa;R. Winglee;S. G. Benka
1993年秋季在美国宇航局戈达德航天飞行中心举行的为期一周的研讨会上，对脉冲太阳耀斑期间粒子加速的现有模型的现状进行了回顾。最近从Yohkoh和康普顿伽马射线天文台的观测，以及对太阳最大使命的旧观测的重新分析，导致了关于耀斑中粒子加速的位置、时间和效率的重要新结果。本审查报告第一部分概述了这些问题。粒子加速过程，然后讨论，特别强调在随机加速磁流体动力学波和直接电场加速子和super-Dreicer电场的新发展。最后，当这些机制被纳入大型火炬结构时出现的问题被考虑。随机和超德莱塞加速可能发生在一个大的日冕重联点或多个“碎片化”的能量释放点。次德雷塞加速需要一个高度浓缩的日冕电流模式。所有理论都需要面对的一个特殊问题是，在耀斑能量释放区域显然需要大的磁场强度。
This paper, a review of the present status of existing models for particle acceleration during impulsive solar flares, was inspired by a week‐long workshop held in the Fall of 1993 at NASA Goddard Space Flight Center. Recent observations from Yohkoh and the Compton Gamma Ray Observatory, and a reanalysis of older observations from the Solar Maximum Mission, have led to important new results concerning the location, timing, and efficiency of particle acceleration in flares. These are summarized in the first part of the review. Particle acceleration processes are then discussed, with particular emphasis on new developments in stochastic acceleration by magnetohydrodynamic waves and direct electric field acceleration by both sub‐ and super‐Dreicer electric fields. Finally, issues that arise when these mechanisms are incorporated into the large‐scale flare structure are considered. Stochastic and super‐Dreicer acceleration may occur either in a single large coronal reconnection site or at multiple “fragmented” energy release sites. Sub‐Dreicer acceleration requires a highly filamented coronal current pattern. A particular issue that needs to be confronted by all theories is the apparent need for large magnetic field strengths in the flare energy release region.