Kinetic simulations of ring current evolution during the Geospace Environment Modeling challenge events

摘要

We investigate the temporal and spatial evolution of the ring current during two storms selected for study by the Geospace Environment Modeling (GEM) program using our kinetic drift-loss model coupled with a time-dependent plasmasphere model. We use geosynchronous data from LANL satellites to model the inflow of plasma from the magnetotail. We compare results from simulations using either Volland-Stern (VS) or Weimer (W01) model of the convection electric field and investigate the relative effect of magnetospheric convection and radial diffusion on the storm-time injection and trapping of energetic particles and ring current asymmetry. Model comparisons with in situ Cluster, NOAA, and Polar energetic particle observations show overall better agreement with W01 than with VS model. On the other hand, VS model reproduced better the evolution of the plasmapause as observed by IMAGE. Additional ring current ion injections caused by radial diffusion near Dst minima improved the agreement with observations.