ELECTRODYNAMIC INTERACTION BETWEEN COMET SHOEMAKER-LEVY-9 AND JUPITER

The electrodynamical interaction between Jupiter and comet Shoemaker-L evy 9, which is expected to impact on Jupiter around July 20, 1994, is investigated. The comet consists of a sequence of 21 or so nuclei, ea ch surrounded by a neutral cloud of outgassed material. A model is con structed of one single such cloud which is subject to electron impact ionization during the passage through Jupiter's magnetosphere. The clo ud is assumed to couple electrically to the surroundings either by mea ns of Alfven wings, or through a dc circuit that closes in Jupiter's i onosphere. The magnetic-field-aligned currents resulting from the Jupi ter-Io interaction are strongly connected to the Jovian Decametric Rad iation.The Shoemaker-Levy comet can theoretically supply ions to Jupit er's magnetosphere at a rate not so far below Io's, and will have a hi gher velocity relative to Jupiter, and could therefore conceivably dri ve similar processes. However, we find that, due to the high latitude trajectory of the comet, the resulting currents become very weak. The field-aligned currents obtained in this study are a factor 500 below t hose driven by lo, while the dissipated power is almost a factor 106 b elow. It is therefore proposed that very little or no detectable elect romagnetic radiation will arise during the comet's passage through Jup iter's