Energetic Electron Precipitation and Atmospheric Impacts: Implications for Space Weather Monitoring

Energetic electron precipitation (EEP) from the inner magnetosphere is a key element of magnetosphere–ionosphere–thermosphere (MIT) coupling and a major driver of space weather impacts on the upper atmosphere. Controlled by wave–particle interactions such as whistler-mode chorus, hiss, and electromagnetic ion cyclotron (EMIC) waves, EEP contributes to auroral emissions, enhanced atmospheric ionization, and NOx production, with important consequences for atmospheric chemistry and dynamics. Robust quantification of EEP and its impacts is therefore essential for advancing space weather monitoring and modelling.

In this study, we present recent advances in lifetime models of energetic electrons developed to quantify EEP driven by whistler-mode chorus waves. Using these models, we perform numerical simulations to calculate precipitating electron fluxes and associated ionization rates. The results demonstrate that additional scattering mechanisms, beyond those included in current state-of-the-art chorus and hiss models, are required to accurately estimate EEP and its atmospheric effects.

These developments build on collaborative efforts of our ISSI team “Precipitation of Energetic Particles from the Magnetosphere and Their Effects on the Atmosphere,” with coordinated activities within ISWAT. Within this framework, we reviewed precipitation mechanisms affecting radiation belt and ring current electrons, assessed potential missing processes, and examined EMIC wave–electron resonance, including constraints on minimum affected energies. Storm-time space weather impacts, including those during the extreme geomagnetic event of 10–15 May 2024, were also discussed.

Finally, we place these observational and modelling efforts in the context of the ESA Study the Energetic Electron Precipitation (SEEP) project, developed in response to the ESA call for a New Earth Observation Mission Idea (NEOMI). SEEP aims to provide new observational constraints on EEP and its atmospheric effects, enabling improved model validation and supporting future space weather monitoring capabilities.