On the Properties of the Ionospheric Convection Drivers

The study presents an extensive statistical analysis of the sources of the ionospheric convection potential for two different global conditions: (1) Steady southward IMF and ionospheric 2-cell convection patterns, typical for a topology dominated by dayside reconnection. (2) Steady northward IMF and ionospheric 4-cell convection patterns, typical for a general lobe-reconnection topology. The data used are from the DMSP F13 satellite, covering the time period of 1996-2004. The derived potentials are compared with solar wind data from OMNI, and the influence of the solar wind parameters on the different potentials are studied in detail. The results show a significantly larger boundary layer potential for the northward IMF case, where the average contribution is on the order of 10 kV (corresponding to roughly 30-35% of the total energy input during northward IMF conditions), compared to the total boundary layer potential for southward IMF which only measures 1-2 kV on average. An analysis of the reverse convection potential, which functions as a good measure of the present energy input due to lobe reconnection, indicate a saturating behavior of the reconnection process for strong solar wind electric fields during northward IMF, similar to that previously reported for dayside reconnection. The saturated potential reaches a limit of around 60 kV, on the order of a fourth of the maximum potential for southward IMF.