Statistical Properties of Quasi‐Periodic Electron Precipitation

Diffuse aurora is an important phenomenon that is responsible for significant magnetospheric energy input into the ionosphere. Pulsating aurora is one distinct type of diffuse aurora, caused by quasi‐periodic electron precipitation with energies ranging from a few keV to tens of keV. Recent studies have suggested that pulsating aurora can also be accompanied by relativistic electron precipitation, which can penetrate into the E/D‐layer of the ionosphere and lead to a significant ionospheric response. However, the energy extent and occurrence rate of the relativistic, quasi‐periodic precipitation are not well understood. In this study, we perform a statistical analysis of quasi‐periodic electron precipitation events observed by the low‐altitude, polar‐orbiting ELFIN CubeSats. Our results show that these precipitation events predominantly occur in the dawn sector, and approximately 15% of them extend to relativistic energies ( keV). Possible mechanisms for the quasi‐periodic relativistic precipitation are also discussed.