Spatial distributions of ions and electrons from the plasma sheet to the inner magnetosphere: Comparisons between THEMIS-Geotail statistical results and the Rice convection model
Spatial distributions of ions and electrons from the plasma sheet to the inner magnetosphere: Comparisons between THEMIS-Geotail statistical results and the Rice convection model
复制标题
从等离子体片到内磁层的离子和电子的空间分布：THEMIS-Geotail统计结果与Rice对流模型的比较
DOI：
10.1029/2011ja016809
复制
发表时间：
2011
影响因子：
--
通讯作者：
A. Lui
中科院分区：
文献类型：
--
作者：
Chih‐Ping Wang;M. Gkioulidou;L. Lyons;R. Wolf;V. Angelopoulos;T. Nagai;J. Weygand;A. Lui
[1] 为了了解等离子体片和环电流粒子的形成和结构的过程，我们使用 THEMIS 和 Geotail 数据统计研究从中尾到内磁层的离子和电子的分布，并将其与莱斯对流模型 (RCM) 的结果进行比较。观察到的分布显示等离子体片粒子的热能和能量通量明显的磁局域时间 (MLT) 不对称性，但更多的 MLT 对称环电流粒子。我们的 RCM 运行包括自洽电场和磁场以及现实的依赖于 MLT 的外部粒子源。从没有初始粒子开始，从 RCM 外部源释放的粒子沿着电和磁漂移路径移动并绝热地改变能量。观察与模拟的比较表明，沿着开放漂移路径的粒子可以解释观察到的等离子体片群体，并且观察到的显着 MLT 变化是物种和能量相关的漂移以及位置相关的源强度的综合结果。发现闭合漂移路径内粒子的模拟能量和空间分布与观察到的环流粒子一致。这些环流粒子最初是等离子体片状粒子，由于漂移路径的时间变化而沿着闭合路径被捕获。 RCM 与观测之间的热能和能量通量的空间分布的关键特征的良好一致性清楚地表明，电和磁漂移输运以及相关的能量在等离子体片和环电流动力学中起着主导作用。
[1] To understand the processes responsible for the formation and structure of plasma sheet and ring current particles, we have used THEMIS and Geotail data to investigate statistically the distributions of ions and electrons from the midtail to the inner magnetosphere and compared them with results from the Rice convection model (RCM). The observed distributions show clear magnetic local time (MLT) asymmetries in the thermal energy and energy fluxes of plasma sheet particles but many more MLT symmetric ring current particles. Our RCM runs include both self-consistent electric and magnetic fields and realistic MLT-dependent outer particle sources. Starting with no initial particles, particles released from the RCM outer sources move along electric and magnetic drift paths and change energy adiabatically. Comparison of the observation with the simulation indicates that the particles along the open drift paths can account for the observed plasma sheet populations and that the observed significant MLT variations are a combined result of species- and energy-dependent drift and location-dependent source strength. The simulated energy and spatial distributions of the particles within closed drift paths are found to be consistent with the observed ring current particles. These ring current particles are originally plasma sheet particles which became trapped along closed paths due to temporal variations of drift paths. The good agreement in key features of the spatial distributions of thermal energy and energy fluxes between the RCM and observations clearly indicates that electric and magnetic drift transport and the associated energization play dominant roles in plasma sheet and ring current dynamics.