Testing the necessity of transient spikes in the storm time ring current drivers

Abstract

Inner magnetospheric numerical simulations of the 17 April 2002 storm are conducted to explore the importance of transient spikes in the driving parameters at controlling the strength of the storm time ring current. The two main factors considered in this study are convection electric field strength and nightside plasma boundary condition. These quantities were smoothed and/or despiked across intervals of 20-180 min. It is found that the spikes contribute linearly to the ring current total energy content. Exceptions to this finding include too much resulting ring current after despiking or smoothing (relative to a linear response). This indicates that at best the relationship is linear and, if the timing of transient spikes in one driving parameter is not coincident with high values in the other main driving parameter, then the response is sublinear (that is, the transient spikes could be less effective than long-time duration increases in the input parameters). Copyright 2011 by the American Geophysical Union.