Magnetic reconnection with Sweet-Parker characteristics in two-dimensionallaboratory plasmas

Magnetic reconnection has been studied experimentally in a well-controlled, two-dimensional laboratory magnetohydrodynamic plasma. The observations ar e found to be both qualitatively and quantitatively consistent with a gener alized Sweet-Parker model which incorporates compressibility, downstream pr essure, and the effective resistivity. The latter is significantly enhanced over its classical values in the collisionless limit. This generalized Swe et-Parker model also applies to the case in which a unidirectional, sizable third magnetic component is present. (C) 1999 American Institute of Physic s. [S1070-664X(99)92105-5].