The solar wind in the Venus ionosheath: examination of mass loading and frictional phenomena

Abstract

A comparative study of the solar wind in the Venus ionosheath, based on the Mariner 5, Venera 9 and 19, and Pioneer Venus spacecraft. is presented. It is shown that the available experimental evidence indicates that. downstream from the bow shock. the solar wind experiences a strong and sudden deceleration in the vicinity of the terminator. The implications of ,this velocity change are further discussed in connection with the effects of chemical processes (mass loading and charge exchange collisions). and frictional phenomena at the ionopause. It is concluded that the former processes are notsufficient to account for the manner in which the solar wind decelerates in that region, and that a strong coupling between that plasma and the topside ionosphere exists near the terminator.