Abstract
Microbursts are an impulsive increase of electrons from the radiation
belts into the atmosphere and have been directly observed in low Earth
orbit and the upper atmosphere. Prior work has estimated that
microbursts are capable of rapidly depleting the radiation belt
electrons on the order of a day, hence their role to radiation belt
electron losses must be considered. Losses due to microbursts are not
well constrained, and more work is necessary to accurately quantify
their contribution as a loss process. To address this question we
present a statistical study of > 35 keV microburst sizes
using the pair of AeroCube-6 CubeSats. The microburst size distribution
in low Earth orbit and the magnetic equator was derived using both
spacecraft. In low Earth orbit, the majority of microbursts were
observed while the AeroCube-6 separation was less than a few tens of km,
mostly in latitude. To account for the statistical effects of random
microburst locations and sizes, Monte Carlo and analytic models were
developed to test hypothesized microburst size distributions. A family
of microburst size distributions were tested and a Markov Chain Monte
Carlo sampler was used to estimate the optimal distribution of model
parameters. Finally, a majority of observed microbursts map to sizes
less then 200 km at the magnetic equator. Since microbursts are widely
believed to be generated by scattering of radiation belt electrons by
whistler mode waves, the observed microburst size distribution was
compared to whistler mode chorus size distributions derived in prior
literature.