Ionospheric flow and escape of ions from Titan and Venus

Abstract

Knowledge gained from measurements and models is used to study the high-speed plasmas interacting with the atmospheres and ionospheres of Titan and Venus. Considering the similarities of the interactions, comparative analysis is used to support the interpretations of observations made at each body. Ionospheric flow, inferred to exist by analysis of measurements made from the Pioneer Venus Orbiter, supports the interpretation of similar flow in the ionosphere of Titan. The concept of cold ion escape from the ionosphere of Venus is supported by the Voyager 1 observation that cold ions escape down the magnetic tail of Titan. Pickup O + ion energy distributions observed at their source in the ionosheath of Venus are shown to be influenced by finite gyroradius effects. The signatures of such effects are expected to be retained as the ions move into the wakes of Titan and Venus.