GEM: A Parametric Study of Geomagnetic Storms during Magnetic Cloud Intervals Using Global MHD Simulations

这个项目的目的是通过分析一组发生在各种不同构型的理想化磁云的模拟，来扩大我们对各种磁云构型对磁层-电离层系统影响的理解。磁场方向的极性似乎是按太阳周期排列的，可能对给定磁云的地质有效性具有决定性作用。此外，磁云常常伴随着行星际激波、高速气流和尾随密度增强。由于无法区分这些潜在的协同特征，对这些相互作用所涉及的基础物理的理解的发展一直受到阻碍。Lyon-Fedder-Mobarry(LFM)全球MHD程序将用于模拟各种磁云条件下的磁层-电离层系统。此外，还将使用二维相对论引导中心粒子代码来模拟辐射带的演化。这项研究将集中在1)改变磁云的极性，2)改变IMF自转间隔的持续时间，3)改变输入到磁层的能量，以及4)包括尾随密度的增强。从模拟中得出的一组基准参数将用于评估哪些特征控制给定配置的地质有效性。

The goal of this project is to expand our understanding of the effects of various magnetic cloud configuration on the magnetosphere - ionosphere system by analyzing simulations for a set of idealized magnetic clouds occur in variety of different configurations. The polarity of the magnetic field orientation appears to be ordered by solar cycle and may have a determining role on the geoeffectiveness of a given magnetic cloud. Furthermore, magnetic clouds are often accompanied by interplanetary shocks, high-speed streams and trailing density enhancements. The development of an understanding of fundamental physics involved in these interactions has been hampered by an inability to separate these potentially synergistic features. The Lyon-Fedder-Mobarry (LFM) global MHD code will be used to simulate the magnetosphere - ionosphere system under a variety of magnetic cloud conditions. In addition, a 2-D relativistic guiding center particle code will be used to mode the evolution of the radiation belts. The study will focus on 1) varying the polarity of the magnetic cloud, 2) changing the duration of the IMF rotation interval, 3) changing the energy input into the magnetosphere, and 4) including trailing density enhancements. A baseline set of parameters derived from the simulation will be used to assess which features control the geoeffectiveness of a given configuration.