Fast magnetic field-line reconnexion in a compressible fluid. Part 2. Skewed field lines

Abstract

Petschek's model of compressible reconnexion developed in part 1 is extended to include an additional transverse magnetic field. Part of the incoming Poynting flux is degraded into kinetic energy at an intermediate wave (rotational) discontinuity. Yet more is degraded into heat and kinetic energy at a slow shock lying downstream of it. Everywhere downstream of the rotational discontinuity, the transverse magnetic field exceeds its upstream value. As a result, the total release of magnetic energy from the antiparallel components of the incoming magnetic field calculated in part 1 is decreased by a factor lying between a half and unity. The weak radial inhomogeneity exemplified by the ‘local’ similarity solution is determined by consideration of the fast and slow magneto-acoustic and Alfvén waves emitted at the neutral point. The Alfvén waves lead to a weak singularity in the vicinity of the rotational discontinuity, while a similar singularity is found in the vicinity of the outflow axis of symmetry associated with an entropy wave.