Speaker
Description
Physics-based models of the radiation belts can provide time-dependent simulations of the high-energy electron flux, taking into account processes such as radial transport, wave-particle interactions, collisions with the atmosphere and losses to the magnetopause. To successfully reproduce observations, the simulations require appropriate boundary conditions and accurate descriptions of each of the processes included in the model. Typically these models are used to simulate specific events or longer periods of up to about year. Here we present a simulation of the high-energy (>100 keV) electron flux in the region between the outer edge of the inner belt and GEO for nearly 3 solar-cycles, made using the British Antarctic Survey Radiation Belt Model (BAS-RBM).
We describe a method that converts the >2 MeV flux measured by GOES at GEO into a differential flux spectrum to provide an outer boundary condition for the simulation. The simulation is validated using independent measurements made by the Galileo In-Orbit Validation Element-B spacecraft; correlation coefficients are in the range 0.72 to 0.88, and skill scores are between 0.6 and 0.8 for a range of L∗ and energies. The results provide a ‘climatology’ of the radiation belts; consistent features are present during different parts of the solar cycle and the average and peak fluxes also vary with the phase of the solar cycle. The worst case spectrum overlaps that derived independently for the limiting extreme event. A comparison between the simulation and the IRENE model identifies the locations and times where the two models differ significantly.
