High-latitude Poynting flux measured by DMSP satellites during magnetic storms

Tuesday, 16 December 2014: 11:41 AM
Yanshi Huang1, Cheryl Y Huang2 and Yi-Jiun Su2, (1)University of New Mexico, Albuquerque, NM, United States, (2)Air Force Research Laboratory Albuquerque, Albuquerque, NM, United States
Previous studies have shown strong enhancement of Poynting flux in the polar cap from observations during magnetic storms, which was comparable to or even larger than that in the auroral zones. We investigate the high-latitude Poynting flux enhancement measured by DMSP satellites (F15, F16, F17 and F18) for quiet and main phases of several storm events in this study. The distribution of Poynting Flux enhancement in the polar region is illustrated with a bin size of 2.5 MLAT and 1 hour MLT. Also the horizontal component of ion drift velocity is used to define the Convection Reversal Boundaries (CRBs), which indicate the area of polar cap. The analysis of two storms on August 6, 2011 and September 26, 2011 shows clear enhancement of nightside Poynting flux that is pole-ward of 80 MLAT and well inside CRBs. It is also found that the polar cap can extend equator-ward to 60 MLAT during main phases. Moreover, the track-integrated Poynting flux shows enhancement in both auroral zone and polar cap during main phases, and the Poynting flux in the polar cap can reach above 90% of the total Poynting flux integrated along the track.