Mapping the Cusp (GEM)

这项建议是要求延续1991年的1年期奖励。我们建议使用从协调的GEM数据运动中获得的数据来测试和完善Toffoletto和Hill的开放磁层模型？关于磁层尖端到低空的映射。该模式定量地预测了局地时间范围和峰顶赤道边界的位置，以及电离层对流的方向和强度作为跨极帽势、IMF方向和太阳风动压的函数。顶点的赤道边界被暂时定义为位于磁鞘声波线向阳方向的日面合并线部分的电离层足迹。我们计划进行模型数据比较，作为检验模型假设和边界条件的一种手段；该测试将为为模型改进设置议程提供指导，其中一些正在开发中。最终，我们期望开发一个尖离子降水模型，通过在模型指定的大尺度磁场和电场中跟踪从日面合并线到电离层高度的粒子分布来计算。

This proposal is a request for the continuation of a 1 year 1991 award. We propose to use data obtained from the coordinated GEM data campaigns to test and refine the open-magnetosphere model of Toffoletto and Hill ?1989! with respect to the mapping of the magnetospheric cusp to low altitude. The model provides quantitative predictions of the local time extent and location of the equatorward boundary of the cusp and the direction and strength of ionospheric convection as functions of the cross- polar-cap potential, IMF direction and solar wind dynamic pressure. The equatorward boundary of the cusp is provisionally defined as the ionospheric footprint of that portion of the dayside merging line that lies sunward of the magnetosheath sonic line. We plan to do model-data comparisons as a means of testing the model's assumptions and boundary conditions; this test will provide a guide for setting an agenda for model improvements, some of which are currently under development. Ultimately, we expect to develop a model of cusp ion precipitation, calculated by tracing a distribution of particles from the dayside merging line to ionospheric altitude within the large-scale magnetic and electric fields specified by the model.