DMSP observations of high latitude Poynting flux during magnetic storms. (November 2017) - Huang, Cheryl Y.
Abstract: Previous studies have demonstrated that energy can enter the high-latitude regions of the Ionosphere-Thermosphere (IT) system on open field lines. To assess the extent of high-latitude energy input, we have carried out a study of Poynting flux measured by the Defense Meteorological Satellite Program (DMSP) satellites during magnetic storms. We report sporadic intense Poynting fluxes measured by four DMSP satellites at polar latitudes during two moderate magnetic storms which occurred in August and September 2011. Comparisons with a widely used empirical model for energy input to the IT system show that the model does not adequately capture electromagnetic (EM) energy at very high latitudes during storms. We have extended this study to include more than 30 storm events and find that intense EM energy is frequently detected poleward of 75° magnetic latitude. Highlights: Poynting flux enters the polar cap during magnetic storms. The observed Poynting flux does not agree with empirical model predictions. Observed Poynting flux is highly dynamic during storms.