PLASMA-DIFFUSION INTO THE WAKE OF VENUS

A model of the diffusion of ionosheath plasma into the wake region of Venus is presented. It is shown that particle diffusion, which is assumed to be a consequence of the fluctuating magnetic field observed in the wake of Venus by Pioneer Venus and Veneras 9 and 10, can explain the plasma observations made in the wake by Veneras 9 and 10. The pressure due to these diffusing particles when balanced against the ionospheric pressure yield ionopause heights less than 1000 km for zenith angles less than about 135°. The model also predicts significant fluxes of low energy electrons and ions for zenith angles less than 135°, which are capable of producing the observed nightside ionosphere. Copyright 1979 by the American Geophysical Union.