Effects of ionospheric O+ on the magnetopause boundary wave activity

In this paper we use a multi-fluid magnetohydrodynamic (MHD) model to explore effects of ionospheric O+ ions on the development of the Kelvin-Helmholtz (KH) instability at the flanks of the earth's magnetopause. The model used is the multi-fluid version of the Lyon-Fedder-Mobarry (LFM) global magnetospheric MHD simulation code. We set up a controlled numerical experiment whereby the solar wind speed is slowly increased resulting in building up the velocity shear across the magnetopause. As this happens, the KH waves at the magnetopause flanks increase their intensity. Along with the solar wind velocity ramp-up, we introduce O+ fluid in the plasma sheet and watch its influence on the development of the KH instability. We find that the simulation with the O+ ions present at the magnetopause shows a significantly weaker KH wave activity on both edges of the low-latitude boundary layer than the simulation without oxygen but identical otherwise.