ON THE INJECTION OF FINE DUST FROM THE JOVIAN MAGNETOSPHERE

Using a simple aligned dipole model of the Jovian magnetic held, and e xploiting integrals of the gravito-electrodynamic equation of motion o f charged dust, we obtain an analytic result which characterizes the n ature of the orbits of grains of different (fixed) charge-to-mass rati os launched at different velocities from different radial distances fr om Jupiter. This enables us to consider various possible sources of th e dust-streams emanating from Jupiter which have been observed by the Ulysses spacecraft. We conclude that Jupiter's volcanically active sat ellite Io is the likely source, in agreement with the earlier calculat ions and simulations of Horanyi et al. using a detailed three-dimensio nal model of the Jovian magnetosphere. Our estimates of the size range and the velocity range of these dust grains are also in good agreemen t with those of the above authors and are within the error bars of the observations.