Intermittent enhancement of magnetic reconnection process in turbulent current sheet

Recent magnetospheric observations and 3D kinetic simulations have shown that plasma wave activities are significantly enhanced around the reconnection x-line, implying that the magnetic reconnection process is fully three-dimensional. However, the impact of the waves and turbulence on the local reconnection process has been poorly understood yet. By means of large-scale particle-in-cell simulations in the 3D system, it has been shown that the thin current layer formed around the reconnection x-line is unstable to the flow shear instabilities, leading to intense electromagnetic turbulence in the diffusion region (1). We find that the local reconnection rate can be intermittently enhanced in the turbulent current sheet, reaching 0.4, much larger than that in 2D reconnection (2). The large reconnection electric field is associated with large energy conversion and strong electron acceleration, leading to production of high-energy electrons. The enhancement of the reconnection rate is attributed to the local increases of electron momentum transport and pressure gradient force induced by turbulence. The result is quantitatively consistent with recent satellite observations where the normalized reconnection electric field shows large variations.

1. K. Fujimoto, and R. D. Sydora (2023), Phys. Plasmas, 30, 022106

2. Y. N. Liu, K. Fujimoto, and J. B. Cao (2024), Geophys. Res. Lett., 51, e2023GL106466