Abstract and subjects
The dynamical coupling of the ring current and the radiation belt populations is investigated during geomagnetic storms, employing recent ring current modeling studies that include time-dependent transport in realistic nondipolar and self-consistently calculated magnetic fields. We present results from a ring current-atmosphere interactions model (RAM) that solves the kinetic equation for H+, O+, and He+ ions and electrons and is two-way coupled with a 3-D equilibrium code (SCB) that calculates self-consistently the magnetic field in force balance with the anisotropic ring current plasma pressure. The RAM-SCB boundary conditions are specified by a plasma sheet source population at geosynchronous orbit that varies both in space and time. It is demonstrated that the storm time ring current development affects radiation belt dynamics in three significant ways: (1) it depresses the background magnetic field on the nightside, which affects the subsequent transport of radiation belt electrons, (2) its electron component represents a highly variable, asymmetric, low-energy seed population of the radiation belts, and (3) the unstable ring current ion and electron populations generate electromagnetic ion cyclotron, magnetosonic, and chorus waves (with different intensities and spatial distributions) that scatter radiation belt particles. Therefore, to understand radiation belt dynamics, we need to consider the coupling in the inner magnetosphere across broad spatial, temporal, and energy scales.