Centrifugally driven diffusion of iogenic plasma

Abstract

The plasma distribution around Io as measured by Voyager 1 displays an asymmetric discontinuity at Io's orbit that has been suggested to be the signature of centrifugally driven interchange diffusion fed by plasma derived from Io. We explore this hypothesis here further and find it to be valid. The particular form for the diffusion coefficient appropriate to centrifugally driven turbulence is derived. The nonlinear character of this kind of diffusion is thereby made explicit. Solutions to the nonlinear, time‐independent and linearized, time‐dependent diffusion equations are given. These display a markedly conservative behavior. The nonlinear, steady state solutions are identical in form to the solutions of the previously studied equation of linear, atmospherically driven diffusion. The linearized, time‐dependent solutions exhibit a negative feed‐back quality that buffers the response of the density to changes in the source strength. Estimates of the source strength, the diffusion coefficient, and the signal propagation speed are also given.