A Statistical Study on the ULF Wave-Driven Ultrarelativistic Electron Flux Oscillations in the Outer Radiation Belt

The objective of this study is to assess the role of radial diffusion by ultralow frequency (ULF) waves on ultrarelativistic electrons in the radiation belts using electron flux oscillations as observed by the Relativistic Electron Proton Telescope on NASA's Van Allen Probes. Previous research has shown that radial diffusion is the result of magnetic and electric field fluctuations and can be characterized in this way (Schulz and Lanzerotti, 1974), and more recently Sarris et al., 2017 has shown that using Van Allen Probe measurements, oscillation in flux amplitude on energetic particle's drift period can also act as an indicator for radial diffusion. This investigation utilizes Fast Fourier Transform (FFT) analyses on electron fluxes to automatically identify the flux oscillation events for ultrarelativistic electrons based on the overall magnitude of power above the background level and the pronunciation of a peak power corresponding to the electron's drift frequency. Using this method, we identify 272 events of 3.4 MeV electrons throughout the year of 2017. We then take this collection of events and conduct a statistical analysis to observe the relationship between electron flux oscillation events and parameters such as solar wind and geomagnetic activity. The results help gain a more in-depth understanding of the relation between electron flux oscillations and radial diffusion for ultrarelativistic electrons in the radiation belts and shed light on the role of radial diffusion on the ultrarelativistic electron dynamics.