Solar Wind Properties During Juno's Approach to Jupiter: Data Analysis and Resulting Plasma Properties Utilizing a 1-D Forward Model

The Jovian Auroral Distributions Experiment ion sensor (JADE-I) on board the National Aeronautics and Space Administration's Juno mission measured solar wind ions for ≈40 days prior to the spacecraft's arrival at Jupiter, simultaneous with numerous telescope observations of the Jovian aurora. JADE-I is a thermal plasma time-of-flight instrument designed to measure Jovian auroral and magnetospheric ions. This study provides a solar wind parameter data set for the approach phase that may be used in coordinated studies with remote measurements of the Jovian aurora, to compare with models that propagate solar wind conditions from Earth and to apply to Jovian bow shock or magnetopause models. While multiple bow shock crossings were predicted during Juno's approach, there was only one observed suggesting a compressed magnetosphere that was shrinking as Juno approached. However, the calculated ram pressure at the bow shock was near the median value of those 40 days, rather than being in an upper percentile.