Modeling the 17 March 2015 CME‐shock driven storm using MHD‐test particle simulations

Abstract:

Both a prompt injection up to MeV energies and an abrupt decrease in the outer boundary of trapped electrons coincided with inward motion of the magnetopause for the 17 March 2015 CME-shock driven storm, the strongest storm (Dst = - 223 nT) of the Van Allen Probes era and last decade. Modeling injection similar to the 8-9 October 2013 storm, much weaker in Dst response (Dst = - 58 nT), and dropout of flux at higher L values includes both trapped and plasmasheet source populations in MHD test particle simulations driven by ARTEMIS data for both storms. The energy dependence of promptly injected electrons is more readily apparent for the 15 March 2015 storm than the 8-9 October 2013, since the Van Allen Probes spacecraft B was on the nightside pre-midnight vs. dayside during shock arrival for the more recent storm. Multifluid Lyon-Fedder-Mobarry simulation including O+ outflow has been implemented improving agreement with GOES magnetometer measurements at geosynchronous orbit over the LFM-RCM and stand-alone LFM-MIX model. Electric field diagnostics from the EFW instrument that were not available for storms immediately following launch have improved our understanding of the complex role that ULF waves play in radial transport during such events. The importance of prompt injections from the tail associated with substorm intervals is captured by the MHD-test particle model reproducing flux at GOES and comparing favorably with Van Allen Probes ECT measurements.