Response of Venus ions to solar wind dynamic pressure

Abstract

Orbiter ion mass spectrometer measurements, as available in the UADS data files are used to study the response of dayside Venus ions at various altitudes to solar wind dynamic pressure, P_sw. Ion densities below about 200 km are not affected by changes in P_sw. At altitudes above 200 km the ions get abruptly depleted with increase in P_sw, and this abrupt depletion occurs at lower altitudes when P_sw is high. At lower P_sw, the depletion occurs at higher altitudes. The effect is similar for all ions. These results are also compared with the empirical relationship observed by Brace et al. (1980) between the ionopause altitude and P_sw from electron density measurements on orbiter electron temperature probe.