Reconnection rate for the inhomogeneous resistivity Petschek model

The reconnection rate for the canonical simplest case of steady-state two-d imensional symmetric reconnection in an incompressible plasma is found by m atching of an outer Petschek solution and an internal diffusion region solu tion. The reconnection rate obtained naturally incorporates both Sweet-Park er and Petschek regimes; while the latter is possible only for a strongly l ocalized resistivity.