Spatial and Energy Dependence of Energetic Electron Precipitation Originating From Jupiter's Inner and Middle Magnetosphere

Abstract

Energetic electron precipitation transfers trapped magnetospheric energy into Jupiter's atmosphere, yet its contribution beyond the main auroral oval has to be fully quantified. This study statistically investigates the atmospheric energy input from electrons in the 30 keV–1.2 MeV range using in situ measurements from the Juno spacecraft, focusing on particles mapping to $M$-shells 2–30 and encompassing the diffuse auroral region. The precipitating energy flux is quantified, dependencies on magnetic local time and System III longitude are examined, and the energy-dependent structure of the precipitation across the magnetosphere is investigated. The results show that electron precipitation equatorward of the main auroral oval contributes a substantial fraction of Jupiter's atmospheric energy budget when integrated over area, and in some regions is comparable to, or exceeds, estimates of the main auroral power. Magnetic local time and longitudinal dependencies are identified, with the latter linked to hemispheric differences in magnetospheric structure and, ultimately, loss-cone geometry. Radial variations further reveal systematic, energy-dependent changes in precipitating electrons as higher latitudes are approached.