Analysis of the Effects of Finite Particle Temperature on Whistler Mode Wave Propagation in the Earth’s Magnetosphere.

Abstract:

Whistler-mode waves in the magnetosphere play an important role in the energy dynamics of the Earth's radiation belts. Calculating the trajectories of whistler mode waves, so called ray tracing, has been exclusively based on cold plasma theory. Here we have extended previous works to include ions in the fully adiabatic warm plasma theory. Using a finite electron and ion temperature refractive index surfaces are calculated for 1-10 kHz whistler mode waves in the inner magnetosphere. A finite ion temperature is found to have a greater effect on the refractive index surface than the electron temperature and the primary effect is to close an otherwise open refractive index surface. Including a finite ion temperature is especially important when the wave frequency is just above the local lower hybrid resonance frequency. The results are used to assess previous conclusions on the efficacy of using in situ whistler-mode sources to precipitate energetic electrons. It is found that the number of in situ sources needed to illuminate the plasmasphere with whistler-mode energy is greater than previously predicted.