Effects of a Realistic O+ Source on Modeling the Ring Current

Abstract

AbstractWe use the UNH‐IMEF electric field model to simulate the convection of O+ from the near‐earth plasma sheet into the ring current during the 17 March 2015 storm. Using Van Allen Probes data from the night side apogee, we reconstruct a realistic O+ source. Modeling this storm using the UNH‐IMEF electric field and a dipole magnetic field has previously been found to have good agreement. Using the realistic source along with drift times and charge exchange loss from these results, we model an inbound pass near the peak of the storm where O+ is increasingly dominant over H+. We find that the time‐varying realistic O+ source is necessary to reproduce the observed spectral features and the O+ pressure enhancements at low L‐shells, while our previous results showed that the H+ was able to be modeled sufficiently with a simple, unchanging boundary condition. Further, our results show that adiabatic convective transport of O+ from the near‐earth plasma sheet (L ~ 6) can explain the observed ring current enhancements.