The effect of Interplanetary Coronal Mass Ejections on the Venusian atmospheric escape

Venus is believed to have once held a significant amount of water on its surface, water that has since disappeared from the planet. This disappearance is linked in part to the interaction of the solar wind with its atmosphere. In this presentation, we will focus on the response of the Venusian atmospheric escape under the effect of extreme solar wind events, such as Interplanetary Coronal Mass Ejections (ICMEs). This study was effectuated with the help of a steady-state global hybrid model, using data taken from Venus Express as reference. In particular, we focus on the influence of the (i) dynamic pressure and (ii) temperature of the ICMEs on the escape of the planetary ions through different escape channels. The effect of the dynamic pressure is examined with two approaches, using a velocity and then a density increase. We find that there is no clear dependence of the O+ ion escape on the dynamic pressure. The temperature of the incoming solar wind positively influences the O+ ion escape, enhancing their escape from the tail.