Initial FAST observations of acceleration processes in the cusp
Initial FAST observations of acceleration processes in the cusp
复制标题
尖点加速过程的初始 FAST 观测
DOI：
10.1029/98gl00936
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发表时间：
1998
影响因子：
5.2
通讯作者：
C. Cattell
中科院分区：
文献类型：
--
作者：
R. Pfaff;J. Clemmons;C. Carlson;R. Ergun;J. Mcfadden;F. Mozer;M. Temerin;D. Klumpar;W.K. (Bill) Peterson;E. Shelley;E. Mœbius;L. Kistler;R. Strangeway;R. Elphic;C. Cattell
FAST卫星观测期间的两次遭遇与地球的尖点附近4000公里。除了沉淀具有各向同性俯仰角分布的磁鞘粒子外，高能粒子数据还揭示了上行离子束、离子二次曲线、下行“倒V”电子分布以及非常窄的强上行电子束。伴随这些加速过程的是各种各样的直流耦合电场和等离子体波。在一个例子中，磁鞘离子的阶梯状注入与上行离子束和下行电子的爆发相关，这表明与这些注入相关的电流建立了局部电势结构，随后驱动加速过程。这些观测结果强调了这样一个事实，即尖点不仅是磁鞘粒子和磁场通过的管道，而且包含一个动态的内部电气结构，可以局部加速粒子，并可能改变沉淀磁鞘粒子群本身。
FAST satellite observations during two encounters with the Earth's cusps near 4000 km are presented. In addition to precipitating magnetosheath particles with isotropic pitch angle distributions, the energetic particle data reveal upgoing ion beams, ion conics, downgoing “inverted‐V” electron distributions, and very narrow, intense upgoing electron beams. A rich assortment of DC‐coupled electric fields and plasma waves accompany these acceleration processes. In one example, step‐like injections of magnetosheath ions are correlated with bursts of upgoing ion beams and downgoing electrons, suggesting that the currents associated with these injections set up local electric potential structures that subsequently drive the acceleration processes. The observations underscore the fact that the cusp is not merely a conduit for the passage of magnetosheath particles and fields, but contains a dynamic internal electrical structure that accelerates particles locally and may alter the precipitating magnetosheath particle populations themselves.