ELECTRON-SCALE SECONDARY MAGNETIC ISLAND NEAR THE RECONNECTION ELECTRON DIFFUSION REGION BY MMS OBSERVATION

Abstract:

Numerical simulations have demonstrated that the electron Kelvin-Helmholtz (K-H) vortex structures can continuously drive the secondary magnetic reconnection and form the secondary magnetic islands. In this paper, we report the first evidence of an electron-scale secondary magnetic island, which formed by the electron K-H instability near the reconnection electron diffusion region in the magnetotail current sheet from MMS observations. This island is included in the electron bulk vortex and almost be concentric with it. An electron diffusion region (EDR) is observed near the island and also included in the vortex. In addition, we also present high-frequency electrostatic waves observed within the electron-scale secondary magnetic island and EDR, which may be associated with magnetic energy dissipation.