Cluster and Double Star observations of dipolarization
Cluster and Double Star observations of dipolarization
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DOI：
10.5194/angeo-23-2915-2005
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发表时间：
2005-11
影响因子：
1.9
通讯作者：
R. Nakamura;Wolfgang Baumjohann;T. Zhang;C. Carr;A. Balogh;K. Fornacon;E. Georgescu;H. Rème
中科院分区：
文献类型：
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作者：
R. Nakamura;Wolfgang Baumjohann;T. Zhang;C. Carr;A. Balogh;K. Fornacon;E. Georgescu;H. Rème
我们研究了当星团和双星（TC-1）位于同一当地时间扇区时，两种不同IMF条件下的双极化事件：2004年8月7日18:00-24:00 UT，在IMF南向/北向扰动期间；2004年8月14日21:00-24:00 UT，在IMF稳定北向期间。Cluster在两段时间内都观察到双极化和快速流动，但TC-1并非如此。在这两个事件中，卫星都在MIRACLE台站的共轭位置附近交叉。通过多点分析技术，利用Cluster确定传播方向/速度，然后与TC-1的扰动进行比较，讨论其时空尺度。8月7日星系团的B - Z扰动传播方向主要是向南传播，有向南传播的分量；8月14日星系团的B - Z扰动传播方向主要是向北传播，有向南传播的分量，并伴有快速气流。我们认为中尾快速流动在耗散过程中的作用可能会因IMF的条件和尾部的构造而有很大的不同。
We studied two types of dipolarization events with different IMF conditions when Cluster and Double Star (TC-1) were located in the same local time sector: 7 August 2004, 18:00-24:00 UT, during a disturbed southward/northward IMF interval, and 14 August 2004, 21:00-24:00 UT, when the IMF was stably northward. Cluster observed dipolarization as well as fast flows during both intervals, but this was not the case for TC-1. For both events the satellites crossed near the conjugate location of the MIRACLE stations. By using multi-point analysis techniques, the direction/speed of the propagation is determined using Cluster and is then compared with the disturbances at TC-1 to discuss its spatial/temporal scale. The propagation direction of the B Z disturbance at Cluster was mainly dawnward with a tailward component for 7 August and with a significant Earthward component for 14 August associated with fast flows. We suggest that the role of the midtail fast flows can be quite different in the dissipation process depending on the condition of the IMF and resultant configuration of the tail.