Satellite Data-Based 3-D Simulation of Kelvin-Helmholtz Instability and Induced Magnetic Reconnection at the Earth's Magnetopause

Abstract : We present a 3-D two-fluid simulation using plasma parameters as measured by MMS on 8 September 2015 concerning the nonlinear development of the Kelvin-Helmholtz instability at the Earth's magnetopause. We observe an extremely rich nonlinear dynamics including the development of a complex magnetic topology, vortex merging, and secondary Kelvin-Helmholtz instability driven by large-scale vortices distributed asymmetrically in latitude. Vortex induced and midlatitude magnetic reconnection coexist and produce an asymmetric distribution of magnetic reconnection events. These results are in good agreement with MMS observations on the same day, in particular for the presence of both equatorial and off-equator reconnection. Regarding the latter only, we note a predominance of reconnection in the Southern Hemisphere during the early nonlinear phase. The estimated effective diffusion coefficient associated with the dynamics is found to be large enough to account for the observed mass transport at the Earth's magnetospheric flanks.