Multi-scale evolution of Kelvin–Helmholtz waves at the Earth's magnetopause during southward IMF periods

At the Earth's low-latitude magnetopause, Kelvin–Helmholtz instability (KHI), driven by velocity shear between magnetosheath and magnetosphere, has been frequently observed during northward interplanetary magnetic field (IMF) periods. However, signatures of KHI have much less southward IMF periods, how develops under explored. Here, we performed a series realistic 2D 3D fully kinetic simulations KH wave event Magnetospheric Multiscale (MMS) mission at dusk-flank magnetopause on September 23, 2017. The demonstrate that primary bends current layer excites Rayleigh–Taylor (RTI), leading to penetration high-density arms into magnetospheric side. This arm disturbs structures vortex produces intermittent irregular variations surface waves which significantly reduces observational probability periodic waves. further in non-linear growth phase KHI, lower-hybrid drift (LHDI) is induced near edge vortices contributes an efficient plasma mixing across magnetopause. large-scale KHI/RTI small-scale fluctuations LHDI are reasonably consistent with MMS observations. These results indicate multi-scale evolution resulting transport as seen may occur IMF.