Bounce‐averaged diffusion coefficients for field‐aligned chorus waves

Abstract

Whistler mode chorus emissions in the Earth's magnetosphere extend from the plasmapause to the boundary of trapping. Knowledge of the pitch angle and energy scattering rates is essential for accurate radiation belt modeling. Scattering rates, which are used as an input for radiation belt codes, should be evaluated dynamically and should account for the changes in plasma density, latitudinal and MLT distribution of waves, and wave spectral properties. Bounce‐averaged diffusion coefficients computed with the assumption of parallel wave propagation are compared to the results of the PADIE diffusion code, which takes into account the oblique propagation of waves and higher‐order resonances. The inaccuracies associated with the neglect of higher‐order resonances are compared to potential errors introduced by inaccuracies in determining plasma density and the latitudinal distribution of waves. Numerical sensitivity tests show that the errors associated with the neglect of the high‐order scattering are smaller than inaccuracies associated with the uncertainties in the parameters of the codes.