Electron density fluctuations in the nightside Venus ionosphere: Role of gravity waves

Abstract

A one‐dimensional, two‐ion (O+, O2+) model is described for studying fluctuations in electron density, electron temperature, and magnetic field produced by atmospheric gravity waves in the low‐altitude (<200 km) ionosphere of Venus just past the terminator (solar zenith angle 100°). Plasma velocity and self‐consistent horizontal magnetic field are calculated utilizing the observed data on plasma densities and temperatures. Effect of the Hall and Pedersen conductivity on the gravity wave dispersion relation is investigated. A gravity wave of time period 33 min and horizontal wavelength 700 km is considered for the case study. Amplitude and phase of electron density, electron temperature, and magnetic field fluctuations relative to the fluctuations in neutral atomic oxygen density are calculated. Results are discussed in the light of observed wave structure and correlations in these parameters. It is found that the fluctuations observed in the ionospheric and magnetic parameters in the nightside ionosphere of Venus can be produced by internal gravity waves.