GEM: Identifying Impact of the Coupling to Ionosphere-Thermosphere on the Near-Earth Electric Fields and Currents

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This is a three-year project to carry out a data analysis and modeling study of the electromagnetic coupling between the Earth?s magnetosphere and the ionosphere-thermosphere system of its extended atmosphere. The mid-latitude ionosphere is a complicated overlap region of processes initiated at high and low latitudes, with each playing a dominant role in the electrodynamics at different times depending on the current level of geomagnetic activity, as well as the pre-conditioning of the system. The overarching goal of this effort is to advance understanding of the physics of the magnetosphere-ionosphere coupling in this region by addressing a number of specific outstanding science questions: 1) how ionospheric conductance and neutral winds affect ring current dynamics and penetration electric fields, 2) how ionospheric conductance and neutral winds impact current closure between the ring current and the ionosphere that drive sub-auroral plasma flows, and 3) mechanisms of corotation lag in the plasmasphere. A framework of models that self-consistently couples the ionosphere-thermosphere with the inner magnetosphere and ring current will be utilized. This capability was recently developed by the proposing team. It will be complemented through this effort by a component that allows for direct comparisons with a large, diverse set of ground-based and satellite measurements, including observations from the newly established mid-latitude radar stations of the SuperDARN network and the newly available global observations of near-Earth magnetic field variations provided by the AMPERE project. The project will foster extended collaborations between the proposing team of modelers and the many NSF supported community facilities providing the multitude of observational data that will be utilized for this study. This will help demonstrate the versatility of these measurements