GEM: Mode Conversion and Kinetic Alfven Waves at the Magnetopause and Their Effects in the Magnetosphere

GEM：磁层顶的模式转换和动力学阿尔文波及其在磁层中的影响

• 批准号: 1405225
• 负责人: Yu Lin
• 金额: $ 46.04万
• 依托单位: Auburn University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-06-01 至 2018-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1405225&HistoricalAwards=false
• 关键词: GEM; Mode; Conversion; Kinetic; Alfven

The transport of mass and momentum into the magnetosphere from the solar wind remains an important but incompletely understood problem. This proposal will study wave-induced particle diffusive processes as a transport mechanism at the dayside magnetopause. In particular the team will investigate the processes involved in the conversion of magnetohydrodynamic (MHD) fast mode waves to kinetic Alfven waves (KAWs). The conversion to KAWs may be an effective mechanism for transport. The processes involved here may be very important in laboratory and astrophysical plasmas as well as at the magnetopause. This research has an important element of basic plasma physics research.The approach will be to use hybrid simulations (kinetic ions and fluid electrons in self-consistent electromagnetic fields) to investigate mode conversion in a local boundary layer. The team will investigate 1) the 3-D nonlinear physics of mode conversion, 2) the physics of mode conversion due to self-consistently generated foreshock compressional waves, 3) the observed signatures of mode conversion and the dependence of mode conversion on interplanetary magnetic field ( IMF) and solar wind conditions, 4) the differences between KAWs due to mode conversion and those due to reconnection and 5) the impact of KAWs on the ionosphere through Poynting fluxes and field aligned currents. Comparison will be made between the simulation results and THEMIS observations in the magnetosphere and DMSP observations in the ionosphere.The research will support a graduate student.

从太阳风到磁层的质量和动量传输仍然是一个重要但尚未完全理解的问题。 这项建议将研究波致粒子扩散过程作为一种传输机制在向阳侧磁层顶。特别是，该小组将研究磁流体动力学（MHD）快模式波转换为动力学阿尔芬波（KAWs）的过程。 转换为KAWs可能是一种有效的运输机制。 这里涉及的过程可能是非常重要的实验室和天体物理等离子体以及在磁层顶。这项研究是基础等离子体物理研究的一个重要组成部分，其方法是使用混合模拟（自洽电磁场中的动力学离子和流体电子）来研究局部边界层中的模式转换。该团队将研究1）模式转换的3-D非线性物理，2）由于自洽产生的前震压缩波导致的模式转换的物理，3）模式转换的观测特征以及模式转换对行星际磁场（IMF）和太阳风条件的依赖性，4）模式转换引起的KAWs与重联引起的KAWs之间的差异; 5）KAWs通过坡印亭通量和场向电流对电离层的影响。将模拟结果与磁层THEMIS观测值和电离层DMSP观测值进行比较。