Stability of Thin Current Sheet in the Magnetotail: Theory, Simulations, and Observations

该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。本研究项目的主要目的是研究膨胀不稳定性、无碰撞重联和其他电流驱动的不稳定性在磁层亚暴的触发和时间演化中的作用。该项目将结合Hall MHD（磁流体动力学）、全动力学粒子池（PIC）模拟和分析理论。该项目将对现实磁尾平衡中气球模式的线性稳定性进行比较研究，以确定等离子体可压缩性和捕获粒子效应在流体和动力学机制中的作用。它还将使用类似的初始条件研究现实磁尾平衡中气球不稳定性的非线性演化，以确定动力学效应是否以及如何改变快速的指数非线性增长。该项目将研究磁尾中扩展薄电流片内电流驱动的动力学不稳定性，以及嵌入薄电流片的磁尾结构中重联、膨胀和其他电流驱动的不稳定性之间的相互耦合。理论和模拟的结果将与欧洲CLUSTER卫星和美国宇航局THEMIS任务的观测结果进行比较。虽然这个项目的重点是应用于磁层物理，但薄电流片的稳定性是一个广泛和跨学科的兴趣课题。特别是，无碰撞重联和气球不稳定性在薄电流片动力学中的作用在日冕物理以及锯齿振荡和聚变和其他实验室等离子体中的电流中断现象中具有重要的应用。该项目还包括一个重要的教育和公共宣传组成部分，其中包括在新罕布什尔大学一个名为SMART项目（通过研究培训取得科学和数学成就）的暑期学院的讲座。SMART项目为高中生提供研究经验。除了PI和能源部资助的洛斯阿拉莫斯国家实验室的合作者外，该项目还涉及一名研究科学家和两名初级教员，其中一名是女性。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The principal goal of this research program is to investigate the role of ballooning instabilities, collisionless reconnection and other current-driven instabilities in the triggering and temporal evolution of magnetospheric substorms. The project will use a combination of Hall MHD (Magnetohydrodynamic), fully kinetic particle-in-cell (PIC) simulations, and analytical theory. The project will carry out a comparative study of the linear stability of ballooning modes in realistic magnetotail equilibria to determine the role of plasma compressibility and trapped particle effects in the fluid and kinetic regimes. It will also investigate the nonlinear evolution of ballooning instabilities in realistic magnetotail equilibria using similar initial conditions to determine if and how kinetic effects modify the rapid exponential nonlinear growth. The project will investigate current-driven kinetic instabilities within extended thin current sheets in the magnetotail, and the interactive coupling between reconnection, ballooning and other current-driven instabilities for magnetotail configurations with embedded thin current sheets. The results of theory and simulations will be compared with observations from the European CLUSTER satellites and NASA's THEMIS mission. Although the focus of this project is on applications to magnetospheric physics, the stability of thin current sheets is a subject of broad and interdisciplinary interest. In particular, the role of collisionless reconnection and ballooning instability in the dynamics of thin current sheets has important applications to coronal physics as well as to sawtooth oscillations and current disruption phenomena in fusion and other laboratory plasmas. The project also includes a significant education and public outreach component, which includes lectures at a summer institute at the University of New Hampshire called Project SMART (Science and Mathematics Achievement through Research Training). The SMART program provides research experiences for high school students. In addition to the PI and the Department of Energy funded collaborator at the Los Alamos National Laboratory, the project involves one Research Scientist and two junior faculty members, one of whom is a woman.