GEM: Development and Application of Magnetospheric Equilibrium Magnetic Field Models

该项目将使用最近开发的地球磁层磁场和压力分布的经验模型作为MHD(磁流体动力)平衡解算器的输入，计算地球内部和中部磁层的一组三维平衡解。拟议的研究项目的一个重要部分将是修改平衡求解器，以包括各向异性压力的影响，并调查这种修改如何影响所产生的平衡。这项工作将为地球空间环境建模(GEM)计划以及更广泛的空间物理界感兴趣的各种建模和数据分析工作创造有用的投入。计算的平衡解以及询问和显示结果的相关软件将提供给广大科学界使用。平衡解将根据经验模型中使用的同一组太阳风条件进行入库。模型结果将被用来解决几个有趣和有意义的科学问题。平衡解将允许检查经验等离子体和磁场模型之间的一致性，以确定独立计算的模型离平衡有多近。此外，平衡结果将被用来研究压力平衡不一致性，并探索导致场向电流产生的等离子体压力和磁场梯度。在磁层内部，环电流压力是各向异性的。一个悬而未决的问题是，等离子体压力各向异性在内部磁层的结构和电动力学中是否扮演着重要的角色？这些新的均衡模型的使用将使回答这一问题和相关问题成为可能。

This project will compute a set of three dimensional equilibrium solutions for Earth's inner and middle magnetosphere using recently developed empirical models of Earth's magnetospheric magnetic field and pressure distributions as inputs to an MHD (magnetohydrodynamic) equilibrium solver. An essential part of the proposed research project will be the modification of the equilibrium solver to include the effects of anisotropic pressure and to investigate how this modification affects the resulting equilibria. This work will create useful inputs for a variety of modeling and data analysis efforts that are of interest to the Geospace Environment Modeling (GEM) program as well as to the wider space physics communities. The computed equilibrium solutions, as well as relevant software to interrogate and display the results, will be made available for use by the scientific community at large. The equilibrium solutions will be binned according to the same set of solar wind conditions as used in the empirical models. The model results will be used to address several interesting and significant scientific questions. The equilibrium solutions will allow for consistency checks between the empirical plasma and magnetic-field models to determine how close the independently calculated models are to equilibrium. In addition, the equilibrium results will be used to investigate the pressure balance inconsistency and to explore the plasma pressure and magnetic-field gradients responsible for the generation of field-aligned currents. In the inner magnetosphere the ring current pressure is known to be anisotropic. An open question is, does plasma pressure anisotropy play an important role in the configuration and electrodynamics of the inner magnetosphere? The use of these new equilibrium models will make it possible to answer this and related questions.