GEM: Impact of Coupling and Feedback Processes in Geospace on Ring Current Dynamics

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The dynamics of the ring current is the predominant source of the magnetic variations that produce a magnetic storm. It is clear from observations over the last solar cycle that ring current dynamics during magnetic storms couples strongly to other regions of geospace. This project will combine models and observations to uncover the linkages and feedbacks between the ring current and these other regions. Two influential factors will be investigated as part of the proposed effort:(1) inner magnetospheric ion precipitation zones and their relation to stretched magnetic configurations, and (2) global sawtooth oscillations and their impact on the ring current. A set of magnetic storms has been selected for detailed comparative analysis during this research project. For each focus topic, it is expected to achieve: (1) clarification of the nature of the selected coupling and feedback mechanism; (2) advancement of our knowledge of geospace as a complex natural system; and (3) improvement of our ability to simulate the magnetospheric system on a global scale. The analysis will employ two codes developed at the University of Michigan. The first is the Ring Current Atmosphere Interaction Model (RAM), which now includes a self-consistent electric field model. The second is the Comprehensive Space Environment Model (CSEM), which now includes two-way coupling between the magnetohydrodynamic (MHD) simulation code and the kinetic Rice Convection Model (RCM), improving the accuracy of the inner magnetospheric results. Data sets used to constrain, validate, and/or drive the simulations include: particle observations on the geosynchronous Los Alamos National Laboratory (LANL) satellites; ion precipitation from National Oceanic and Atmospheric Administration/Polar Operational Environmental Satellites (NOAA/POES); thermal plasma observations and polar cap potential from the Defense Meteorological Satellite Program (DMSP) satellites; Energetic Neutral Atom (ENA) images from Imager for Magnetopause-to-Aurora Global Exploration/High Energy Neutral Atom (IMAGE/HENA) and Medium-Energy Neutral Atom (MENA) instruments; plasmasphere observations from IMAGE/EUV (Extreme Ultraviolet Imager); magnetic field observations from Geostationary Operational Environmental Satellites (GOES); and ground-based magnetometer data. The study will be the basis for a graduate student's Ph.D. dissertation. Study results will improve scientific understanding of a number of unanswered magnetic storm questions and the results will be made public through presentations and publications. The project will benefit society by improving scientific understanding of some important physical processes responsible for space weather effects, such as Global Positioning System (GPS) errors and satellite anomalies.