GEM: Exploring the Relative Influence of Different Classes of Ion Outflow on the Coupled Dynamics of the Magnetosphere-Ionosphere-Thermosphere System

University Corporation For Atmospheric Res, Boulder CO

Investigators

Abstract

The Geospace Environment Modeling (GEM) program addresses the most critical problems in magnetospheric physics. It is focused research where the topics are selected by the scientific community based on their importance and timeliness. An understanding of dynamics of the magnetosphere requires a quantitative understanding of the sources of the plasma. There are two main sources of plasma for the magnetosphere: the solar wind and the ionosphere. In order to understand the solar wind, magnetosphere and ionosphere system it is important that both sources of plasma be included in models of the overall all system. Most emphasis over the years has been on the solar wind source. This proposal will quantify the outflow from the ionosphere. The approach in this study will be to use the Coupled Magnetosphere Ionosphere Thermosphere (CMIT) simulation system including a new, flexible polar wind outflow module (IPW). The resulting simulation code will be made available to the entire space physics community through the Community Coordinated Modeling Center (CCMC). This study will address two questions: 1) which classes of ion outflow have the most significant effects on the coupled magnetosphere-ionosphere-thermosphere (MIT) system and 2) to what extent do the effects of ion outflow on the coupled MIT dynamics depend on the mechanism producing the outflow? Three versions of the polar wind module will be developed: 1) a classical polar wind model, 2) a configuration where the upper boundary conditions on the polar wind are set by the magnetospheric model, thereby allowing centrifugal forces and pressure gradients to provide the outflow, and 3) a configuration which includes a heuristic model of transversely accelerated ions regulated by inputs like the Alfvenic Poynting flux. The three types of outflow will be evaluated by calculating their influences on the polar cap potential, Dst, hemispheric outflow rates and hemispheric power, and qualitative changes in the magnetospheric convection.