Wave Distribution Functions of Plasmaspheric Hiss and their Effects on Radiation Belt Dynamics

Abstract:

Plasmaspheric hiss is formed by whistler-mode waves which play an important role in the dynamics the Earth's radiation belts, specifically in connection with the slot region between the inner and outer Van Allen belts. The origin of plasmaspheric hiss is still a subject of discussions and these waves are known for their complex propagation properties. They are often far from a single plane wave approximation, forming a continuous distribution of the wave energy density with respect to the wave vector direction (wave distribution function).
Analysis of polarization and propagation parameters of these waves provides us with inputs for modeling of radiation belt dynamics. We use the data of the Waves instrument of Electric and Magnetic Field Instrument Suite and Integrated Science (EMFISIS) onboard the Van Allen Probes spacecraft, to analyze simultaneous measurements of all electric and magnetic field components, together with measurements of the plasma density based on the determination of the upper hybrid resonance frequency. Using this unique data set we estimate the wave distribution functions of plasmaspheric hiss and we model the effects of these waves on the decay rates of radiation belt electrons through quasilinear pitch angle diffusion.