Detection of a hot plasma component within the core regions of Jupiter's distant magnetotail

Abstract

We have combined the Voyager 2 low‐energy plasma data from the Plasma Science Experiment (PLS) and the magnetic field data from the Magnetometer Experiment (MAG) with the Voyager 2 Low Energy Charged Particle Experiment (LECP) ion data (E > 28 keV) for the previously described distant magnetotail observations (5000 < R < 9000 RJ). We show for the first time a definite enhancement of LECP fluxes within the core regions where the PLS densities and magnetic field pressure are lower than surrounding regions, indicating that this hot tenuous plasma is present within the core regions. In general there is a strong anticorrelation between PLS density and LECP fluxes, while a less pronounced anticorrelation between magnetic field pressure and LECP fluxes is observed. Estimates of LECP pressures suggest that this hot plasma will provide the previously described missing pressure in the core if heavy ions dominate the ion composition. The angular dependence of the LECP data indicates a flow of this hot plasma in the anti‐Jupiter direction. This outflowing plasma could be the remnant of the magnetospheric wind observed near Jupiter by LECP. On the basis of this preliminary study we have identified the core regions as having similarities to a plasma sheet.