Neutral Wind Control of Jupiter's Non‐Auroral Ionosphere

Abstract We use JAMMIES (JAMMIES is Another Model Making Ionospheric EStimates), a new model of Jupiter's non‐auroral ionosphere, to demonstrate that neutral wind‐driven field‐aligned plasma transport can explain decades of measurements inconsistent with a solar‐dominated ionosphere. Two observations highlight these inconsistencies: a minimum in emission along the magnetic equator where solar ionization maximizes, and a systematic asymmetry where vertical dawn plasma densities exceed those at dusk. JAMMIES models the chemical and dynamical evolution of plasma in a dipole coordinate system. Observed emissions can be reproduced via two mechanisms: (i) field‐aligned neutral‐ion collisions driven by a steady‐state global neutral wind pattern, or (ii) field‐perpendicular electrodynamic plasma drifts at the magnetic equator. Mechanism (i), induced by persistent auroral heating, also reproduces disparate vertical plasma profiles. Results show that neutral wind‐driven dynamics dominate Jovian ionospheric structure, which is found to be spatially variable but temporally stable.