A statistical study of superfast atmospheric precipitation of radiation belt electrons observed by POES satellites

Atmospheric precipitation of radiation belt electrons plays an important role in the magnetosphere-ionosphere-atmosphere coupling system, which can trigger chemical and electric effects in the upper atmosphere and meanwhile generate aurorae of various types. In the regime of the quasi-linear theory, it is commonly accepted that the population of trapped electrons is no smaller than the precipitated population. However, such a concept has been proved to break down due to the nonlinear wave-particle interactions, which can drive the superfast electron precipitation. Therefore, on basis of the long-term MEPED datasets of POES satellites, we perform a comprehensive analysis of the spatiotemporal characteristics and geomagnetic dependence of superfast radiation belt electron precipitation. Our results demonstrate that superfast atmospheric precipitation of energetic electrons occurs with a non-negligible percentage with respect to the overall electron precipitation observations, and has the geomagnetic dependence similar to that of whistler-mode chorus waves.