Magnetospheric whistler mode ray tracing in a warm background plasma with finite electron and ion temperature. Issue 7 (15th July 2017) - Maxworth, A. S.
Abstract: Whistler mode waves play a major role in the energy dynamics of the Earth's magnetosphere. Numerical ray tracing has been used for many years to determine the propagation trajectories of whistler mode waves from various sources, both natural and anthropogenic. Previous work has been under the ideal cold plasma assumption even though temperatures of the background ions and electrons are in the range of several eV. We perform numerical ray tracing with the inclusion of finite electron and ion temperatures to more accurately model the plasma environment of the Earth's magnetosphere. Finite temperature effects are found to play a significant role in the whistler mode refractive index surface only when the wave frequency is near the lower hybrid resonance frequency and the wave normal angle is oblique. In such cases, the primary effect on whistler mode propagation is to lower the refractive index magnitude and increase the group velocity with slight modifications to the ray trajectories. Landau damping is shown to increase slightly with the inclusion of finite temperature. Key Points: Inclusion of thermal effects modifies the whistler mode wave trajectories close to the lower hybrid resonance and oblique wave normal angles For frequencies near the lower hybrid resonance and at highly oblique angles, inclusion of temperature increases group velocity Landau damping slightly increases with the inclusion of finite electron and ion temperature