Electron-only magnetic reconnection in plasma turbulence.

We present hybrid-Vlasov-Maxwell (HVM) simulations of plasma turbulence including electron-inertia effects. When fluctuation energy is directly injected near ion-kinetic scales, the ions become de-magnetized around naturally forming electron-scale current sheets, in which efficient electron-only reconnection occurs. We show that these electron-only reconnection events are characterized by electron jets unaccompanied by ion outflows, in agreement with recent MMS measurements taken in the Earth's turbulent magnetosheath region (downstream of the bow shock). We conjecture that this kind of turbulent regime is typical of systems in which plasma processes, such as velocity-space instabilities and/or shocks, modify the cascade by injecting energy close to the ion-kinetic scales. We also demonstrate that this reconnection physics and the accompanying turbulent dynamics is consistent with an electron-magnetohydrodynamic description applied to the scale interval between the ion and electron inertial lengths and, in particular, around the reconnection layers.