Pitch-angle diffusion of radiation belt electrons within the plasmasphere

The goal of this work is to explain the formation of the quiet-time electron slot, which divides the radiation belt electrons into an inner and an outer zone. The authors quantitatively investigate the pitch-angle diffusion of radiation belt electrons resulting from resonant interactions with the observed plasmaspheric whistler-mode wave band. The effects of wave propagation obliquely to the geomagnetic field direction with the resulting diffusion at all cyclotron harmonic resonances and the Landau resonances are evaluated along with the effects of interactions occurring at all geomagnetic latitudes. The results account for the long term stability of the inner radiation zone, the location of its outer edge as a function of electron energy, and the removal of electrons to levels near zero throughout the slot. Computed pitch-angle distributions and precipitation decay rates are in good agreement with slot-region observations. (Author)