The Interaction of Fast Magnetosonic Waves with Energetic Electrons in the Van Allen Radiation Belts




Journal Title

Journal ISSN

Volume Title



The outermost region of our atmosphere (> 1000 km) is known as the magnetosphere. One sub region in the magnetosphere primarily contains highly energetic electrons (> 100 keV) and is known as the Van Allen radiation belts. The levels of radiation in this region are dangerous and have been associated with satellite damage and elevated radiation exposure to astronauts. Charged particles in this region undergo three quasi-periodic motions: gyration about the background field, bouncing along the field line, and drifting azimuthally around the Earth. In this thesis we investigate the bounce resonant interaction between fast magnetosonic plasma waves and energetic electrons in the radiation belts. We find that, through test-particle simulation, equatorially mirroring electrons become sufficiently removed from the equatorial plane when a single magnetosonic wave has a frequency that matches the harmonics of the electron bounce frequency. Using Van Allen Probe data we identify an event of a magnetosonic wave event and an electron butterfly pitch-angle distribution in the Van Allen radiation belts. Using our model, we show that bounce resonance with magnetosonic waves is sufficient to produce similar pitch angle distributions. Furthermore, we derive analytic diffusion coefficients due to bounce resonance from our model and compare them with diffusion coefficients from previous studies and perform a parametric analysis on the system.



Magnetospheric physics, Plasma waves, Resonance, Van Allen radiation belts, Electrons