Development of Turbulent Magnetic Reconnection in a Magnetic Island

In this paper, with two-dimensional particle-in-cell simulations, we report that the electron Kelvin-Helmholtz instability is unstable in the current layer associated with a large-scale magnetic island, which is formed in multiple X-line guide field reconnections. The current sheet is fragmented into many small current sheets with widths down to the order of the electron inertial length. Secondary magnetic reconnection then occurs in these fragmented current sheets, which leads to a turbulent state. The electrons are highly energized in such a process.