Dynamics of Relativistic Reconnection

The dynamics of the steady state Sweet-Parker-type reconnection is analyzed in the relativistic regime when energy density in the inflowing region is dominated by the magnetic field. The structure of the reconnection layer (its thickness and inflow and outflow velocities) depends on the ratio of two large dimensionless parameters of the problem: the magnetization parameter σ ≫ 1 (the ratio of the magnetic to particle energy densities in the inflowing region) and the Lundquist number S. The inflow velocity may be relativistic (for S < σ) or nonrelativistic (for S > σ), while the outflowing plasma is always moving relativistically. For extremely magnetized plasmas with σ ≥ S2, the inflow four-velocity becomes of the order of the Alfvén four-velocity.