Dynamics of relativistic reconnection
  The dynamics of the steady-state Sweet--Parker-type reconnection is analyzed in relativistic regime when energy density in the inflowing region is dominated by magnetic field. The structure of reconnection layer (its thickness, inflow and outflow velocities) depends on the ratio of two large dimensionless parameters of the problem - magnetization parameter $\sigma \gg 1$ (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< \sigma$) or non-relativistic (for $ S > \sigma$), while the outflowing plasma is moving always relativisticly. For extremely magnetized plasmas with $\sigma \geq S^2$, the inflow four-velocity becomes of the order of the \Alfven four-velocity. 
Maxim Lyutikov (1), Dmitri Uzdensky (2) ((1) McGill University,   Massachusetts Institute of Technology, CITA National Fello...