High-Latitude Poynting Flux: A Statistical View from DMSP

Abstract:

We present a statistical study of Defense Meteorological Satellite Program (DMSP)-derived Poynting flux (PF) from five spacecraft-years of magnetometer and ion-drift data. The data, acquired in both hemispheres between 2000 and 2012, provide a refined view of electromagnetic energy deposition from earlier Dynamics Explorer-2 and ASTRID spacecraft studies. The PF calculation is made only when ion-drift data are available for both horizontal plasma drift components. Automated baseline and spike removals are applied to the drift and magnetic data. We bin the median PF by IMF components and by the location of energy deposition in terms of polar cap, auroral zone or sub-auroral zones. The latter categorization is made with DMSP particle boundaries. A strong pattern of pre-noon polar cap PF deposition appears in both hemispheres. We identify longitudinally-extended channels of PF that appear to associate with the subauroral polarization streams (SAPS) and with the dawnside auroral polarization streams (DAPS).