Magnetosphere-Ionosphere Coupling and Associated Ring Current Energization Processes

Adiabatic processes in the ring current are examined. In particular, an analysis of the factors that parameterize the net adiabatic energy gain in the inner magnetosphere during magnetic storms is presented. A single storm was considered, that of April 17, 2002. Three simulations were conducted with similar boundary conditions but with different electric field descriptions. It is concluded that the best parameter for quantifying the net adiabatic energy gain in the inner magnetosphere during storms is the instantaneous value of the product of the maximum westward electric field at the outer simulation boundary with the nightside plasma sheet density. However, all of the instantaneous magnetospheric quantities considered in this study produced large correlation coefficients. Therefore, they all could be considered useful predictors of the net adiabatic energy gain of the ring current. Long integration times over the parameters lessen the significance of the correlation. Finally, some significant differences exist in the correlation coefficients depending on the electric field description.