Plasma Sheet Boundary Layer in Jupiter's Magnetodisk as Observed by Juno

Abstract

AbstractThe Juno spacecraft has been orbiting Jupiter for the past 3 years. During this interval, Juno has collected large datasets of plasma, magnetic field, and wave measurements in Jupiter's magnetosphere. In this study, we conduct statistics on the plasma and wave characteristics in Jupiter's magnetodisk (nightside magnetosphere beyond 20 Jupiter radii, RJ). Distributions of electron fluxes and waves in the magnetodisk exhibit different characteristics in two regions: the plasma sheet with dense plasma and weak wave intensity and the plasma sheet boundary layer (PSBL) occupied by strong waves and rarefied plasma. We discuss that these waves can be generated by field‐aligned high‐energy electrons in the PSBL. We further compare plasma and wave properties in the PSBL of Jupiter's magnetodisk with the PSBL in Earth's magnetotail. This comparison suggests that the PSBL in Jupiter's magnetodisk may be formed by transient magnetic reconnection in the Jovian magnetosphere. The dawn‐dusk asymmetry of the PSBL properties further supports this scenario: the PSBL is more pronounced in the dawn flank of Jupiter's magnetodisk, where magnetic reconnection is predicted to occur by models of the rotation‐dominated magnetosphere. We further discuss properties of the Jovian PSBL and implications on magnetic reconnection in Jupiter's magnetosphere.