Identification of slow waves in the evolution of KHI near the Venusian ionopause

Abstract

Abstract The MHD slow waves in the evolution of Kelvin–Helmholtz instability (KHI) near the Venusian ionopause has been identified by using the magnetohydrodynamics equations. The diagnosis of slow waves utilizes two criteria: the phase speed and the ratio of density oscillation to the velocity oscillation. With the speed of sound greater than Alfvén speed, the phase velocity of slow waves along the initial magnetic field is approximately equal to Alfvén speed. For slow waves, the ratio of the density oscillation to the velocity oscillation along the initial magnetic field is independent of the angle between wave vector and the magnetic field. The data from the side of low-density were analyzed around the KH vortex. The numerical simulation results show that there are slow waves in the induced magnetosphere near the magnetopause of Venus. We also note that during the nonlinear growth stage, the parallel oscillations contribute approximately 76% ∼ 93% to the wave energy. This work will provide more clues that the KHI is a possible source of slow waves observed near Venus-like planets.