The Repetition Period of MeV Electron Microbursts as Measured by SAMPEX/HILT

Here we examine properties of MeV electron microbursts to better understand their generation mechanisms. Using 15 years of data from Solar, Anomalous, Magnetospheric Particles Explorer/Heavy Ion Large Telescope, >1 MeV microburst repetition periods (time spacing between bursts) are examined and clear dependencies on Auroral Electrojet (AE), L shell, and magnetic local time (MLT) are discovered. Microburst repetition periods are shortest around 0–6 hr MLT and 4–5 L shell, and grow longer toward the day and afternoon sectors and larger L shells. Shorter repetition periods (<1 s) are also found to be more common during higher AE, while longer periods (>10 s) more common during quiet times. The microburst repetition period distributions are compared directly to those of rising tone chorus wave elements and found to be similar in the night, dawn and day MLT sectors, suggesting chorus wave repetition periods are likely directly controlling those of microburst precipitation. However, dusk-side distributions differ, indicating that the dusk-side microbursts properties may be controlled by other processes.