Survey of Bow Shock and Magnetopause Boundaries Observed by Juno

Characterizing the relationship between the solar wind and Jupiter’s magnetosphere is crucial for understanding its role in the variability of the bow shock and magnetospheric standoff distances and boundaries. Although the magnetosphere is predominantly supported by internal plasma pressure, the solar wind nevertheless plays a significant role in the shape, location, and size of the overall magnetosphere structure. Since Juno arrived at Jupiter in June of 2016, it has completed over 1600 crossings through the magnetopause and bow shock, which have been identified by examining particle and wave measurements from the Juno instruments. We compare these crossings with data from previous missions (e.g., Pioneer, Voyager, and Galileo) to compile an extensive database of crossings, allowing for thorough investigation of the magnetopause and bow shock boundaries. Previous models of the Jovian system do not account for extremely high solar wind dynamic pressures that cause strong compressions of the magnetosphere, such as the event observed in October of 2024, when the magnetopause boundary—usually located between 60-100 Rj upstream of Jupiter—was found as close as 35 Rj. We derive scaling factors of these models at various solar wind dynamic pressures, such as the Joy et al. 2002 model, in order to explore a correlation between such compressed standoff distances and the solar wind.