STABILITY OF THE IO PLASMA TORUS ATMOSPHERE INTERACTION

The stability of the Io plasma torus-atmosphere interaction is examine d. A simple plasma deflection model describes how transients in the pl asma flux and the content of the atmosphere affect the ionospheric con ductance, limiting the plasma bombardment and, hence, the supply of at mospheric species to the torus. The supply of the torus is seen to be determined by the thermal structure of the plasma, namely, the amount of low energy plasma producing atmospheric erosion vs. that which prod uces ionization, so that the torus supply rate is not simply proportio nal to the torus ion density.