RBSPICE Observations of the March 17, 2015 Geomagnetic Storm

We investigate the time evolution of the pitch angle distributions of H, He, and O during the March 17, 2015 geomagnetic storm. We use a Bayesian updating procedure to track observables obtained from RBSPICE data through the storm's progression. The procedure is more sensitive to the time rate of change of these observables than is a simple maximum likelihood procedure (the running average), making it a useful tool for resolving the storm-time suppression of trapped particle fluxes. We draw tentative conclusions about the global storm-time particle dynamics on this basis.