Individual features in this stable structure are known as curtains. Even when the two vehicles are separated in time by over a minute, both measure roughly the same structured time profile of radiation intensity, offset by the time separation between vehicles. The pair of low altitude, polar AeroCube-6 satellites observed stable small-scale structure in the electrons present in low Earth orbit (LEO). We conclude that one viable explanation for many of the curtains observed by the AeroCube-6 pair is the accumulation of drift-dispersed microburst electron byproducts in the drift loss cone. We use test particle tracing in a dipole magnetic field to show that spatially stationary source regions generating periodic microbursts can produce curtain signatures azimuthally downstream. Statistical studies of where and when curtains occur have indicated that some, but not all, curtains could be caused by microbursts. The spatial structure that remains reflects the pattern of microburst sources. When observed at downstream azimuths by a satellite equipped with an integral energy sensor, no bounce phase structure remains, or, equivalently, the same time profile is present when two such satellites pass by many seconds apart. Electrons in the drift loss cone remain on the field line and bounce-phase mix over subsequent bounces while also drifting in azimuth. Each of these emissions in turn produces a microburst of electron precipitation, filling the drift and bounce loss cone on the local field line.
NASA OMNIWEB SERIES
The microburst formation hypothesis states that a source region in the equatorial region produces a series of very low frequency chorus wave emissions.
The electrons involved have energies of 10–100s of keV. Precipitation curtains are latitudinal structures of stable precipitation that persist for timescales of 10s of seconds or longer. We explore the hypothesis that electron precipitation curtains such as those observed by the AeroCube-6 satellite pair can be produced by electron microbursts.
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