Poynting flux input to the auroral ionosphere: The impact of subauroral polarization streams and dawnside auroral polarization streams

The Joule heating controls fundamental ionospheric properties affecting the entire magnetosphere-ionosphere-thermosphere system, so it is necessary to understand when and where the Poynting flux is significant. Taking advantage of new data sets generated from DMSP (Defense Meteorological Satellite Program) observations, we investigate the Poynting flux distribution within and around the auroral zone, where most magnetosphere-ionosphere (M-I) dynamics and thus Joule heating occurs.

We find that the Poynting flux, which is generally larger under more active conditions, is concentrated in the sunlit cusp and near the interface between Region 1 and 2 currents. The former concentration suggests voltage generators drive the cusp dynamics. The latter concentration shows asymmetries with respect to the interface between the Region 1 and 2 currents.