Bursty Bulk Flows, Dipolarization Fronts, and Particle Energization in the Substorm Plasma Sheet

该项目将研究在磁亚暴期间地球磁尾等离子体片的突发体流、双极化锋和高能粒子通量增强。本文将研究四个具体问题：(1)双极化锋与地磁变化的关系，以及地面磁场观测是否与双极化锋的振幅有关；(2)偶极锋是如何形成的，它是如何随时间演变的，是什么控制了它的振幅；(3)在亚暴期间，双极化锋在向近地等离子体层注入高能等离子体中所起的作用（如果有的话）；(4)确定爆炸体流是否在产生高能等离子体注入中起作用，或者它们是否仅仅是高能等离子体从中尾向近地等离子体层传输的方式。该项目将利用来自THEMIS卫星航天器的数据、基于地面的磁场变化测量和粒子模拟。该项目将使人们更好地了解导致高能粒子注入近地等离子体层的物理过程，以及这些高能粒子如何在磁层内传输。高能粒子在空间天气现象中起着重要作用。这项工作还将提高对与磁重联有关的等离子体现象的理解，磁重联不仅在地球的磁层和电离层，而且在太阳风、其他行星的磁层和天体物理等离子体中都是一个重要的过程。该项目将包括两名研究生的支持和参与。

This project will investigate bursty bulk flows, dipolarization fronts, and energetic particle flux enhancements in Earth's magnetotail plasma sheet during magnetic substorms. Four specific topics will be investigated: (1) How dipolarization fronts are related to the geomagnetic variations and whether or not magnetic observations on the ground are related to the amplitude of the dipolarization front; (2) How a dipolization front is formed, how it evolves with time, and what controls its amplitude; (3) The role dipolarization fronts play (if any) in the injection of energetic plasma into the near-Earth plasma sheet during substorms; (4) Determine whether or not bursty bulk flows play a role in creating energetic plasma injections or if they are simply the way energetic plasma is transported from the mid-tail to the near-Earth plasma sheet.The project will utilize data from the THEMIS satellite spacecraft, ground-based measurements of magnetic field variations, and particle simulations.The project will lead to an improved understanding of the physical processes that lead to the injection of energetic particles into the near-Earth plasma sheet and how those energetic particles are transported within the magnetosphere. Energetic particles play in important role in space weather phenomena. The work will also lead to improved understanding of plasma phenomena related to magnetic reconnection which is a process of importance not only in Earth's magnetosphere and ionosphere but also in the solar wind, in the magnetospheres of other planets and in astrophysical plasmas. The project will include support for and participation by two graduate students.