Non-ideal electric field induced by turbulence in the reconnection diffusion region

Most of the plasma fluid equations have employed the electrical resistivity to generate the magnetic dissipation required for magnetic reconnection to occur in collisionless plasma. However, there has been no clear evidence that such the model is indeed appropriate in the reconnection diffusion region in terms of the kinetic physics. To address this issue, the present study has performed a large-scale 3D particle-in-cell simulation for the anti-parallel and no guide field configuration as well as analytical analysis. The simulation results show 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. It is found that the non-ideal electric field in the diffusion region is consistent with the Ohm's law based on viscosity rather than resistivity (1, 2). The effective viscosity is caused by the turbulence that gives rise to effective momentum transport of the electrons across the diffusion region. The present result suggests a fundamental modification of the fluid equations using the resistivity in the Ohm's law. Our presentation will cover the simulation results and analytical analysis to demonstrate the dissipation mechanism in the turbulent current layer to drive magnetic reconnection. 1. K. Fujimoto, and R. D. Sydora (2021), Astrophys. J. Lett., 909, L15. 2. K. Fujimoto, and R. D. Sydora (2023), Phys. Plasmas, 30, 022106.