Role of solar wind on the ionic escaping from Venus upper ionosphere via plasma wakefield

Abstract

Abstract According to the observations that detected significant ionospheric escape from Venus, a test charge approach is suggested to explain the ionic loss caused by the solar wind (SW) interaction with the Venusian upper ionosphere. The proposed plasma system consists of two positive planetary ions (H + and O +) with isothermal electrons and streaming SW protons, with Maxwellian electrons. The electrostatic Debye screening and wakefield potentials caused by a moving test charge as well as the modified dielectric constant of the ion-acoustic waves (IAWs) created in the model are derived. The normalized Debye potential is found to decrease exponentially with the axial distance. Whereas the amplitude of the wakefield potential is amplified with the altitudes and decreases with increasing the density of either planetary oxygen or the SW protons but it is enhanced by SW electrons number density. However, the wakefield amplitude is not affected by the SW protons velocity or their temperatures because the SW protons velocity is fast compared with the velocity of the plasma system. Thus, the properties of the ions escaping are affected by the velocity variations within a certain range called the velocity scale window. The obtained results are found to be in a good agreement with the observed data.