The Saturation Regime of the Polar Cap Potential Under Southward IMF - A Statistical View

We report the results of an investigation of solar wind properties on the saturation of the polar cap potential during periods of strongly southward IMF. We used propagated solar wind data to search for events between 1998 and 2007 where the interplanetary electric field was in the “saturation” regime of driving, and placed further conditions on the availability of SuperDARN and DMSP velocity data. Polar cap potential values calculated from these data sets were then compared to a linear fit to determine the extent of polar cap potential saturation. It was found that the extent of polar cap potential saturation has statistically significant, but weak, correlation with solar wind Alfvenic Mach number and no significant correlation with solar wind dynamic pressure or the Alfven wing transmission coefficient.