Formation of an extended halo of hot oxygen atoms in the wake region of venus

From the detailed measurements in Venusian ionosphere by the Pioneer Venus Orbiter, it was well-known that there is a large day-to-night flow of ionospheric plasma with the horizontal speed reaching a value as high as 5 km/s at 500 km altitude near the terminator. This large-scale anti-sunward convective motion could lead to a significant distortion of the hot oxygen corona maintained by oxygen atoms from O+ 2 dissociation recombination into a tadpole-like structure. A Monte-Carlo model is developed to simulate the two-dimensional configuration of such a hot oxygen corona.