QUASI-LINEAR PITCH-ANGLE DIFFUSION-COEFFICIENTS - RETAINING HIGH HARMONICS

Diffusion coefficients for electrons pitch angle scattered by plasmasp heric hiss are reconsidered, as given by quasi-linear theory, overcomi ng practical problems in keeping high cyclotron harmonics n. Upper bou nds are used to identify ranges of latitude, n, and wave-normal angle which give only negligible contributions, so that the detailed computa tion of these values may be avoided, resulting in large savings of com putational effort. A simple way of obtaining precipitation lifetimes f rom the diffusion coefficients is also given, using a shooting method. The lifetimes and steady state fluxes are computed, leading to shorte r lifetimes and lower fluxes than previously reported, for energies ab ove 500 keV and McIlwain parameter L greater than 3.