Map of Jupiter's Radiation Environment From Juno's In-Situ Observations

Abstract

Since its orbit insertion on 4 July 2016, the Juno spacecraft has orbited Jupiter in a highly elliptical, polar orbit. With every orbit, Juno's line of apsides migrates, increasing the angle relative to the Jovian equator. Therefore, the spacecraft traverses across the inner regions of the radiation belt, where energetic particles are trapped. The most energetic particle fluxes (electrons with energy >20 MeV) are continuously monitored by an instrument that is part of the Magnetic Field investigation, the micro Advanced Stellar Compass (μASC), which serves as an attitude reference for the magnetic sensor. In the regions traversed thus far in the mission, the μASC has obtained in-situ measurements of high-energy particle fluxes from those on open field lines to Io's L-shell, densely covering the flux environment. We present a map of the radiation environment within Jupiter's magnetosphere based on in-situ measurements acquired in regions not well sampled by prior missions.