Microburst Precipitation in the first BARREL campaign

Relativistic electron microburst precipitation is one of the primary mechanisms that account for significant relativistic electron losses from the outer belt. During the 2013 campaign of BARREL (the Balloon Array for Radiation-belt Relativistic Electron Losses), several episodes of microburst precipitation were observed. Even though all the events were relatively "soft" (e-folding energy less than 100 keV), two events are of special interest. The first happened on 20 January, when the balloon that observed the microbursts was in conjunction with one of the Van Allen Probes spacecraft, providing an opportunity to correlate precipitation characteristics with the state of waves, plasma, and trapped particles at the equator. The second event happened on 2 February and was detected simultaneously by two balloons separated by two hundred miles. By searching for correlations in the x-ray emission from the two balloons on second and subsecond timescales, we will place limits on the size and particle content of individual microbursts. For both events, we will present spectroscopy of the BARREL microburst episodes and analysis of their time profiles in the time and frequency domains, comparing these to events that don't appear to be made up of microbursts. For the episode during spacecraft conjunction, we will present simultaneous data from the Electric Fields and Waves (EFW) instrument and other instruments on the Van Allen Probes.