Modeling the effects of radial diffusion and plasmaspheric hiss on outer radiation belt electrons

摘要

We simulate the behaviour of relativistic ( 976 keV) electrons in the outer radiation belt ( 3 <= L <= 7) during the first half of the CRRES mission. We use a 1d radial diffusion model with losses due to pitch- angle scattering by plasmaspheric hiss expressed through the electron lifetime calculated using the PADIE code driven by a global Kp- dependent model of plasmaspheric hiss intensity and f(pe)/ f(ce). We use a time and energy- dependent outer boundary derived from observations. The model reproduces flux variations to within an order of magnitude for L <= 4 suggesting hiss is the dominant cause of electron losses in the plasmasphere near the equator. At L = 5 the model reproduces significant variations but underestimates the size of the variability. We find that during magnetic storms hiss can cause significant losses for L <= 6 due to its presence in plumes. Wave acceleration is partially represented by the boundary conditions.