GEM: Development and Application of Magnetospheric Equilibrium Magnetic Field Models

William Marsh Rice University, Houston TX

Investigators

Abstract

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.