Microburst Scale Size Derived from Multiple Bounces of a Microburst Simultaneously Observed with the FIREBIRD-II CubeSats

Abstract

We present the observation of a spatially large microburst with multiple bounces made simultaneously by the FIREBIRD‐II CubeSats on February 2nd, 2015. This is the first observation of a microburst with a subsequent decay made by two co‐orbiting but spatially separated spacecraft. From these unique measurements, we place estimates on the lower bounds of the spatial scales as well as quantify the electron bounce periods. The microburst's lower bound latitudinal scale size was 29 ± 1 km and the longitudinal scale size was 51 ± 1 km in low earth orbit. We mapped these scale sizes to the magnetic equator and found that the radial and azimuthal scale sizes were at least 500 ± 10 km and 530 ± 10 km, respectively. These lower bound equatorial scale sizes are similar to whistler‐mode chorus wave source scale sizes, which supports the hypothesis that microbursts are a product of electron scattering by chorus waves. Lastly, we estimated the bounce periods for 200‐800 keV electrons and found good agreement with four common magnetic field models.