Magnetic reconnection with Sweet-Parker characteristics in two-dimensional laboratory plasmas

Magnetic reconnection has been studied experimentally in a well-controlled, two-dimensional laboratory magnetohydrodynamic plasma. The observations are found to be both qualitatively and quantitatively consistent with a generalized Sweet-Parker model which incorporates compressibility, downstream pressure, and the effective resistivity. The latter is significantly enhanced over its classical values in the collisionless limit. This generalized Sweet-Parker model also applies to the case in which a unidirectional, sizable third magnetic component is present.