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

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 K p -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.

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