Dependence of quasi‐linear diffusion coefficients on wave parameters

Abstract

Bounce‐averaged diffusion coefficients, traditionally written as double integrals over latitude and wave normal angle, have recently been expressed as double integrals over wave normal angle θ and wave frequency ω. The integrand is the diffusion coefficient due to a single wave, and the total diffusion coefficient is a weighted average of the single‐wave values. This formulation essentially factors out the wave power distribution in ω and θ, so that the effects of changes in these distributions may be evaluated without extensive recalculation, and may even be estimated visually from general plots. This approach may also be applied directly to narrowband waves. Results indicate that the transmission of waves propagating near the resonance cone, as may occur in the upcoming Demonstration and Science Experiments satellite mission, may be relatively ineffective at precipitating trapped electrons.