Plasmaspheric and Local Time Dependence of Balloon Observed Relativistic Electron Precipitation

Tuesday, 16 December 2014
Leslie A Woodger1, Jerry Goldstein2, Robyn M Millan1 and Alexa Halford1, (1)Dartmouth College, Hanover, NH, United States, (2)Southwest Research Institute San Antonio, San Antonio, TX, United States
The 2013 and 2014 Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) campaigns launched 40 balloons and observed relativistic electron precipitation (REP) in the noon to midnight magnetic local time (MLT) sector. The local time dependence of REP events is consistent with SAMPEX observations and previous balloon missions [ Comess et al., 2013, Foat et al., 1996, Millan et al., 2002, Clilverd et al., 2007]. This study collectively investigates the MLT correlation to the observed x-ray energy spectrum from previous balloon observations of REP events and those observed by the BARREL campaign. A series of relativistic electron precipitation events observed by the BARREL balloons on Jan. 17, 2013 shows a connection between these events and plasmapause boundary crossings. Therefore, this study is extended to consider the relationship between the observed REP x-ray energy spectrum and the plasmapause. Understanding the duskside dependence and relative location to plasmaspheric boundaries of these events may lead to a better understanding of the mechanism causing the observed precipitation.