Determining the State of Jupiter’s Magnetosphere Using In Situ and Remote Sensing Observations

Abstract While Jupiter’s magnetosphere is primarily governed by internal processes, variations in solar wind conditions can significantly modulate magnetospheric energy. Assessing solar wind conditions at Jupiter has been a long-standing challenge in the community. In this study, we investigate multiple datasets, including auroral images captured by the Hubble Space Telescope and in situ measurements obtained by the Juno spacecraft, to characterize Jupiter’s magnetosphere during solar wind compression and quiet conditions. The distinct responses demonstrate that auroral morphologies, lobe magnetic fields, ultra-low-frequency waves, and broadband kilometric radio emissions could serve as effective indicators for magnetospheric states. In particular, we statistically analyze the distribution of lobe magnetic fields, which represent the intensities of the cross-field electrical currents in the magnetodisc, and propose the applicability of the lobe magnetic field as a proxy for solar wind conditions. The results from the four individual methods of determining magnetospheric states are generally consistent, providing further evidence of their robustness. These observational proxies for solar wind conditions could therefore be widely applied in both existing spacecraft datasets and those from future missions to Jupiter.