Data Analysis of the High-Energy Ion Tail in Earth's Plasmasphere

Abstract

The Van Allen Probes Mission has provided an opportunity to examine the ion high-energy (1-10 eV) tail of the cold plasmasphere and it's interaction with plasma waves. We statistically analyze from February 2013 to April 2015 of Van Allen Probes Helium Oxygen Proton Electron (HOPE) data, looking at quiet times with a Kp index of less than 3. We investigate the high-energy population of the plasmasphere, which consists of ions at energies between 1 and 10 eV and contains approximately 5% of total plasmaspheric density. Both the fluxes and partial plasma densities over this energy range show H+ is depleted the most in the post-midnight sector (1-4 magnetic local time). We determine wave-particle interactions cause the dayside 1-10 eV H+ population to be suprathermally heated on the dayside which depletes across the nightside and results in a minimum in the post-midnight sector.