Modeling the inner Jovian electron radiation belt including non-equatorial particles

During the 1990s, multi-dimensional physical models of the electron and proton radiation belts of the Earth have been developed at ONERA/DESP. Three-dimensional (3D) models (latitude, radial distance and energy; plus time) and 4D (latitude, longitude, radial distance and energy; plus time) have been built in action-angle phase space and are now available for the interior of the Earth's magnetosphere (Beutier, Thesis Report, ENSAE, 1993; Beutier and Boscher, J. Geophys. Res. 100(A8) (1995) 14853; Bourdarie, Thesis Report, ENSAE, 1996). During the past years, the 3D electron code, Salammb (o) over cap 3D, has been adapted to Jupiter's radiation environment. The model makes use of adiabatic invariant theory and solves the governing Fokker-Planck transport equation out to 6 Jovian radii, for electrons with energies between 100 keV and 300 MeV and with equatorial pitch-angles between 0 and 90 degrees (i.e. equatorial and non-equatorial Jovian electrons). To explain the trapped electron dynamics in the innermost Jovian magnetosphere, several physical processes must be modeled: local losses due to satellites and rings, energy friction and pitch-angle diffusion due to Coulomb collisions, energy and pitch angle frictions induced by the synchrotron radiation process, and radial diffusion. To simplify the problem, loss rates are averaged over the particle drift path so that the time resolution is reduced to several Jovian days. The localized electron losses from moon and ring sweeping effects appear to be significant processes in the formation of the Jovian radiation belts. The resulting structure depends strongly on the electron drift velocity, and electron flux maps are presented. Comparisons with Pioneer 10 and 11 spacecraft data are also presented and substantiates our model. (C) 2001 Elsevier Science Ltd. All rights reserved.