GEM: Magnetosphere-Ionosphere Coupling--Theory and Modeling of Small-Scale Auroral Currents and Fields

GEM：磁层-电离层耦合——小尺度极光电流和场的理论和建模

• 批准号: 0201703
• 负责人: Robert Lysak
• 金额: $ 21万
• 依托单位: University of Minnesota-Twin Cities
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-15 至 2006-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0201703&HistoricalAwards=false
• 关键词: GEM; Magnetosphere; Ionosphere; Coupling; Theory

The electromagnetic coupling between the ionosphere and the magnetosphere ultimately takes place through small-scale currents and fields. Auroral arcs form on scales smaller than 1 kilometer. This project will investigate the processes by which electromagnetic energy can be transferred to these small scales in the topside auroral ionosphere. It will focus on two of primary processes: (1) linear phase mixing of Alfven waves where there are perpendicular gradients in the Alfven speed, and (2) nonlinear interactions between Alfven waves trapped in the ionospheric Alfven resonator. The research will be carried out by using two and three dimensional simulations of the propagation of Alfven waves using a nonlinear MHD code. The currently existing linear MHD code will be modified to include electron inertial effects along auroral field lines. It will include the effects of the formation of density cavities and the outflow of ions along auroral field lines.

电离层和磁层之间的电磁耦合最终是通过小规模的电流和磁场发生的。 极光弧形成的尺度小于1公里。 该项目将调查电磁能在顶部极光电离层中转移到这些小尺度的过程。 它将集中在两个主要过程：（1）线性相位混合的阿尔芬波有垂直梯度的阿尔芬速度，和（2）非线性相互作用的阿尔芬波被困在电离层阿尔芬谐振器。 研究将通过使用二维和三维模拟阿尔芬波的传播，使用非线性MHD代码进行。 将修改现有的线性MHD代码，以包括沿沿着极光场线的电子惯性效应。 它将包括密度空洞的形成和离子沿沿着极光场线流出的影响。