On the equatorial confinement and velocity space distribution of satellite ions in Jupiter's magnetosphere

Abstract

Configuration and velocity space distributions of ions originating in the neutral particle rings of Galilean satellites are derived under the assumption of radial transport by flux tube interchange diffusion with constant first and second adiabatic invariants. In configuration space the ions from a satellite are found to be confined to a constant thickness disc at Jovicentric distances beyond the satellite (in agreement with the result of Hill and Michel (1976)); the thickness of the disc varies among the satellites. At interior distances the ions are confined to an approximately constant latitude conical disc. The ions from the four satellites occupy well-separated and characteristic regions in velocity space, the details of which are functions of Jovicentric distance. In general, at any distance the perpendicular and parallel components of the thermal velocity (relative to the common corotation velocity) of ions from the various satellites increase monotonically in the natural order from Io to Callisto.