Venus-solar wind interaction:: Asymmetries and the escape of O+ ions

We study the interaction between Venus and the solar wind using a global three-dimensional self-consistent quasi-neutral hybrid (QNH) model. The model treats ions (H+, O+) as particles and electrons as a massless charge neutralizing fluid. In the analysed Parker spiral interplanetary magnetic field (IMF) case (IMF = [8.09, 5.88,0]nT), a notable north-south asymmetry of the magnetic field and plasma exists, especially in the properties of escaping planetary O+ ions. The asymmetry is associated with ion finite gyroradius effects. Furthermore, the IMF x-component results in a dawn-dusk asymmetry. Overall, the QNH model is found to reproduce the main observed plasma and magnetic field regions (the bow shock, the magnetosheath, the magnetic barrier and the magnetotail), implying the potential of the developed model to study the Venusian plasma environment and especially the non-thermal ion escape. (c) 2006 Elsevier Ltd. All rights reserved.