Electron scattering loss in Earth's inner magnetosphere: 2. Sensitivity to model parameters

Abstract

The sensitivity of the rate of energetic electron pitch angle scattering and precipitation loss in the Earth's magnetosphere due to Coulomb interactions with thermal plasma and resonant wave‐particle interactions with plasmaspheric hiss, lightning‐generated whistlers and VLF transmitter signals is computed for a realistic range of plasma and wave parameters. The computed scattering rates are most sensitive to the choice of mean wave frequency and the average angle of propagation; the frequency bandwidth and angular spread in propagation direction are relatively unimportant. Variations in plasma density can also strongly modulate the effectiveness of wave‐particle interactions. The average intensity of plasma waves controls electron lifetimes, but has little effect on the shape of the equilibrium pitch angle distribution function. All three classes of waves must be included together with Coulomb collisions in any realistic analysis of inner magnetospheric electron scattering. The long‐term energetic electron population beyond the inner belt is largely controlled by plasmaspheric hiss and, to a lesser extent, by lightning‐generated whistlers, while VLF transmitter signals constitute the principal loss mechanism over the range 1.3 ≤ L ≤ 2.4. The region below L = 1.3 is dominated by Coulomb collisions.