The Role of Nonlinear Resonant Interactions in Energetic Electron Precipitation: Insights from ELFIN Observations

Energetic electron precipitation from the outer radiation belt is a key mechanism of electron loss in Earth’s magnetosphere. This precipitation is largely governed by resonant interactions between electrons and electromagnetic ion cyclotron (EMIC) waves or whistler-mode waves. For sufficiently intense waves, these interactions become inherently nonlinear, characterized by rapid timescales and substantial precipitating fluxes that fall outside the framework of classical quasi-linear diffusion. In this presentation, we provide an overview of ELFIN CubeSat observations, showcasing compelling evidence of precipitation driven by nonlinear resonant interactions. We further discuss potential approaches for integrating the effects of these nonlinear interactions into radiation belt modeling frameworks.