Modeling the dynamics of outer radiation belt electrons

Abstract

A computer model has been built to simulate the dynamic evolution of relativistic electrons in the outer radiation belt. The model calculates changes in electron flux due to three mechanisms: (1) fully-adiabatic response of electrons to variations in the magnetic field, (2) time-dependent radial diffusion, parameterized by overall magnetospheric activity, and (3) penetration of new particles into the model via a time-dependent outer boundary condition. Data from Los Alamos geosynchronous satellites, the CRRESELE statistical electron flux model, the Kp index, and the Toffoletto-Hill-Ding magnetic field model are all used to provide realistic, time-dependent inputs to the model. To evaluate the model, a simulation of the radiation belts during the November 3--12, 1993 magnetic storm was generated. Comparison of results to Global Positioning System (GPS) radiation dosimeter data indicates that the model can accurately predict storm-time flux variations for electrons with energies less than 600 keV. Modeled fluxes for higher energy electrons show insufficient enhancement during the recovery phase of the storm, suggesting the existence of an acceleration mechanism other than fully adiabatic variations and radial diffusion.