THE IMPACT OF COMET SHOEMAKER-LEVY-9 ON THE JOVIAN MAGNETOSPHERE

By the time of the impact of comet P/Shoemaker-Levy 9 with Jupiter, th e freshly-broken surfaces of the accompanying rubble will have been ou tgassing for about two years, and will have produced an expanding and co-moving cloud of gas hundreds of R(J) across. Much of this gas, esca ping from the cometary fragments at low (less-than-or-equal-to 1 km/s) speed, will arrive in the Jovian magnetosphere contemporaneously with the comet and drift through the magnetosphere. This gas, as it is pho toionized, will be picked up primarily in the outer magnetosphere and the resulting high-energy ions should intensify magnetospheric process es, such as Io plasma torus and auroral emissions, that are thought to be powered by outer magnetospheric mass loading. If the composition o f the comet is similar to that of P/Halley, the power available from m ass loading should be comparable to that driving the aurora (10(14)W) and at least an order of magnitude larger than that exciting the plasm a torus for several weeks or months. Measurement of these emissions du ring and after the cometary encounter may constrain the mechanisms for energization of magnetospheric charged particle populations and magne tospheric transport processes.