Exploring Kelvin Helmholtz Instability in the Magnetopause and Relativistic Regime

In space and astrophysical plasmas, shear flows upstream of reconnection current sheets may affect the onset of reconnection. For instance, it has been recorded that the evolution of Kelvin Helmholtz instability (KHI) in such shear flows can induce reconnection in the Earth's magnetopause. To better define the criteria for instability of the Kelvin Helmholtz mode in the relativistic regime, several modeling systems were used to explore KHI driven by velocity shear. An ideal MHD solver was developed to recreate the results of Miura (1982) showing the growth rate of the KHI for non-relativistic plasmas. Results from this solver, using plasma parameters collected by MMS in the magnetosphere, were compared to the results which identify KHI in the magnetopause during southward interplanetary magnetic field (IMF) periods. A relativistic kinetic simulation, performed using VPIC software to explore KHI in that regime, has produced results nominally consistent with previous non-relativistic VPIC simulations.