Mapping Jupiter's outer radiation belt

Flux maps of energetic ions in Jupiter's outer radiation belt, calculated with the aid of a model of the current sheet magnetic field, are consistent with a spatial distribution that is uniform along field lines and monotonically decreasing with radial distance. This result is supported by numerical ion trajectory calculations that predict uniform filling of drift shells at high L values. Adiabatic compression by radial transport then provides predictions of radial energy dependence and flux gradients. At lower L values, conservation of the second adiabatic invariant predicts some anisotropy with higher equatorial fluxes.