Large Scale Magnetotail Dynamics and Auroral Precipitation

这项提议概述了磁尾中离子和电子的大尺度动力学所引起的极光弧形成的研究。第一步是构造离子分布函数矩(密度、温度、压力等)。在一个三维大尺度磁层模型中。这将使用大规模动力学技术来完成，其中数千个离子轨迹从各种来源发射到磁层的磁场和电场模型中。将确定三维极光降水剖面(与当地时间有关)，并与观测值进行比较。第二步将是使用电子进行类似的大规模动力学研究，之后将比较离子和电子的结果，并在存在电荷不平衡的区域施加平行电场。然后将计算沉淀的电子通量，并产生理论极光图像。第三步是在大尺度动力学模型中引入时间相关性。这将通过使用代表不同状态(即，增长阶段、恢复等)的不同领域模型“快照”来实现。并计算离子和电子的沉淀分布。一旦获得了使用这些快照的一般理解，将尝试通过将安静的时间场模型在时间上演变为更受干扰的时间来对增长阶段进行建模。最后一步是将所有这些结果结合起来，描绘出极光弧线的形成。将确定磁尾中导致极光弧大纵向范围的物理机制，并将结果与观测结果进行比较。

This proposal outlines a study of the formation of auroral arcs caused by the large scale dynamics of ions and electrons in the magnetotail. The first step is to construct ion distribution functions moments (density, temperature, pressure, etc.) in a three-dimensional large scale magnetospheric model. This will be done using the technique of large scale kinetics, whereby thousands of ion trajectories are launched from a variety of sources into a magnetic and electric field model of the magnetosphere. The 3D auroral precipitation profile (with local time dependence) will be determined and compared with observations. The second step will be to perform a similar large scale kinetic study using electrons, after which the ion and electron results will be compared and in regions where there are charge imbalances, parallel electric fields will be imposed. The precipitated electron flux will then be calculated and theoretical auroral images will be produced. The third step is to introduce time dependence into the large scale kinetic model. This will be done by using different field model "snapshots" which represent different states (i.e., growth phase, recovery, etc.) of the magnetosphere and calculating the ion and electron precipitation profiles. Once a general understanding using these snapshots has been achieved, an attempt will be made to model the growth phase by temporally evolving the quiet time field model to a more disturbed time. The last step is to bring all of these results together to delineate the formation of auroral arcs. The physical mechanisms in the magnetotail that result in the large longitudinal extent of auroral arcs will be identified and the results will be compared to observations.