在空间中对称磁再连接过程中扩散区域的电子尺度动态
R B Torbert1,2, J L Burch2, T D Phan3
1University of New Hampshire, Durham, NH, USA. roy.torbert@unh.edu.
概括
磁层多尺度航天器观察到地球磁尾中的快速磁再连接. 电子喷射达到15,000公里/秒, 揭示了扩散区域内的层状电子动态.
科学领域:
- 太空物理
- *等离子体物理
- * 天体物理学
背景情况:
- 磁性重新连接是天体物理等离子体中基本的能量转换过程.
- * 地球的磁层提供了一个可访问的实验室,用于在现场进行连接研究.
- 之前的研究已经探讨了重新连接,但电子尺度动态仍然是一个活跃的研究领域.
研究的目的:
- * 在地球磁尾中重新连接时调查电子尺度的动力学.
- * 描述电子扩散区域和相关的等离子现象.
- * 在重新连接过程中确定电子行为的性质 (层状与流).
主要方法:
- * 通过四个磁层多尺度 (MMS) 航天器进行现场测量.
- 在磁尾再连接事件中分析电子尺度等离子体和场数据.
- * 对电子速度分布和空间结构的研究.
主要成果:
- * 观测到超阿尔弗尼克电子喷射超过15,000公里/秒.
- * 确定了电子的曲运动和加速,形成了半月形的速度分布.
- * 确定电子扩散区域面积比在0.1和0.2之间,符合快速重新连接.
- * 尽管附近有流,但主要显示了层状电子动态.
结论:
- *MMS观测证实了磁尾中具有明显电子动态的快速磁性重新连接.
- 电子加速和曲是扩散区域内的关键过程.
- * 电子群体的层状性质表明在这个事件中有一个结构化的,而不是混乱的电子反应.
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