Modeling the Coupled Ring Current -- Plasmasphere System

We discuss the dynamics of charged particles in the coupled inner magnetosphere in response to the Sun's varying energy output. During periods of increased solar and geomagnetic activity charged particles are injected from the magnetotail, and being transported sunward and accelerated, build the storm time (main phase) ring current. During storm recovery phase the ring current decays through charge exchange with geocoronal hydrogen, Coulomb collisions with thermal plasma, ion precipitation, and convective dayside outflow. The anisotropic ring current populations generate plasma waves which could subsequently accelerate and/or scatter radiation belts particles. We simulate the temporal and spatial evolution of the ring current during the April and June 2001 geomagnetic storms using our kinetic drift-loss model coupled with a time-dependent plasmasphere model. We use geosynchronous data from LANL satellites to model the magnetospheric inflow of plasma on the nightside and demonstrate the importance of storm time plasma sheet enhancement and dropout for ring current buildup and decay. We discuss ring current morphology, ion composition, source and loss processes during various storm phases. Strong EMIC waves are excited near minimum Dst and during the recovery phase of the storms and cause significant particle precipitation into the atmosphere and generation of detached proton auroral arcs.