Insight Into Io Enabled by Characterization of Its Neutral Oxygen Torus

Abstract The Jovian system is very intriguing with extremely different particle sources. As the dominant source of particles to Jupiter's magnetosphere, Io particular importance. JAXA Hisaki (SPRINT‐A) mission providing insightful observations regard Io. In particular, its UV neutral oxygen line sight provide best glimpse so far populations. This exciting in that for first time, tori can be directly observed on time scales constrain satellite data also sheds unprecedented insight into torus distributions, which could subsequently essential information about sources and mechanisms from However, 3‐D modeling required interpret complex dynamic observational geometries. Here, we present distribution Io‐generated using as constraints characterization magnetospheric resulting tori. Major findings our research include: (a) effective total original SO 2 rate during a low activity period ∼800 kg/s; (b) has two separate exospheric sources: O at ∼200 kg/s ∼400 (c) escape preferentially Jupiter upstream facing hemisphere; (d) populates entire orbit significantly dominates over , SO, S toroidal clouds; (e) large ionization dissociation rates limit significant expansion Io‐genic magnetosphere beyond ∼2 Rj Io's orbit.