The most detailed studies of the Venus' ionosphere were carried out before the middle of the 80th years. These works, that considered the ionization by cosmic rays in an ion-neutral model, concluded that Venus should have a lower ionospheric peak due to cosmic rays of 8x103 cm-3 at around 65 km and noted the importance of negative ions and aerosols in the ionospheric structure of Venus at this altitude. We present a new model of Venus' lower ionosphere by making use of the actual knowledge of Venus' aeronomy. In adition to the ionization rate by cosmic rays, the model incorporates a detailed ion-neutral model which includes more neutral and ions species and reactions rates than previous works. The interaction between cosmic rays and the Venusian atmosphere, with a massive amount of CO2 and abundant in species able to be charged negatively, produces a high variety of positive and negative ions. The high atmospheric density at the lower part of the atmosphere makes very efficient the production of the massive ions, that are not present in the upper ionosphere due to solar radiation. The knowledge of the ion composition and understanding of the ion chemistry below the main ionization peak is required to fully understand the atmo- spheric electricity problems and wave propagation. We calculate the concentration of electrons and most abundant ions in the atmosphere of Venus below 120 km.
|Publication status||Published - 1 Jan 2002|