GEM: Validating Self-Consistent Inner Magnetospheric Models: Assessing Effects of Uncertainties in Plasma Sheet and Electric Field Boundary Conditions on Simulating Storms

Aerospace Corporation, El Segundo CA

Investigators

Abstract

This project will examine the uncertainties in the magnetospheric cross polar cap potential (CPCP) and in the plasma sheet population and how these uncertainties affect the intensity and spatial distribution of the magnetospheric ring current during magnetic storms. It will examine how much of the disagreements between models and observations of the ring can be attributed to the uncertainty in the boundary conditions rather than other causes such as missing physical processes in the models. Previous simulation studies have shown that changes in the magnetospheric convection electric field and the plasma sheet distribution, which is the major source to the ring current, strongly influence the ring current. For this reason, success in modeling common ring current observables, such as the Dst index, ground magnetic perturbations and magnetic field at geosynchronous orbit, and plasma parameters is dependent on knowing the CPCP and the plasma sheet densities and temperatures. Because of limited spatial and temporal resolution of in-situ measurements of such quantities, averages from statistical re-analysis or empirical models are often used to specify the boundary conditions for inner magnetospheric models. However, there are large uncertainties associated with these boundary condition specifications. This project will quantify how sensitive simulated storms are to the uncertainties in the CPCP and in the ion and electron plasma sheet density and temperature boundary conditions of self-consistent inner magnetospheric models. The approach is to investigate the statistical variations of plasma sheet parameters measured by the NASA THEMIS spacecraft and the CPCP from DMSP (Defense Meteorological Satellite Program) measurements relative to reference models commonly used to provide simulation boundary conditions. For these data sets, a statistical model of the residual errors of reference models for CPCP and central plasma sheet parameters will be developed. The multivariate error covariance statistics will be computed and Monte Carlo scenarios of the plasma and electric field boundary conditions will be generated. In some cases, the Monte Carlo scenarios will be constrained by available in-situ data. For the different boundary conditions scenarios, the magnetically and electrically self-consistent Rice Convection Model-Equilibrium (RCM-E) will be used to simulate Dst, ground magnetic perturbations and magnetic field and plasma parameters at geosynchronous orbit. By comparing the metrics for the different boundary condition scenarios, the project will determine whether the RCM-E is physically sufficient given the uncertainties in the boundary conditions, or whether it needs additional physical processes. This project will help determine whether researchers need to continue to focus on adding more realistic physics to models of the ring current or if they should shift their focus toward improving the specification of the boundary conditions the control the models. Ultimately it will pave the way to generating ensemble space weather nowcasts and forecasts of the inner magnetosphere's plasma and fields. The project is headed by a woman scientist and also involves research ties between industry (Aerospace Corp.) and universities.