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.