S. Perraut, R. Gendrin, A. Roux
Nov 1, 1976
Journal of Atmospheric and Solar-Terrestrial Physics
Abstract The influence of magnetospheric parameters (such as cold and hot plasma densities, anisotropy and thermal energy of the hot particles) on the growth rate of ion cyclotron waves is investigated in detail. Following the inward penetration of protons having different parallel resonant energies E R , we have computed the integrated growth rate Γ at any radial distance L and plots of iso-Γ contours in the E R - L plane are presented. Conditions for having large amplification inside or outside the plasmasphere are discussed. A comparison between the energy E M of the ‘most interacting’ protons (those which interact with frequencies for which Γ is maximum) and the parallel thermal energy E ∥ of the distribution, has been made in order to determine which part of the distribution function is involved in the interaction. Comparison is also made between E M and the critical energy E c = (B 2 2μ 0 N) A −2 (A + l) −1 and some conclusions regarding the proton precipitation patterns are drawn. The present calculations do not suffer from any approximation and is valid for any cold to hot plasma density ratio.