On the Reconnection of Magnetic Field Lines in Compressible Conducting Fluids

A previous study by Yeh and Axford of the reconnection of magnetic field lines in an incompressible fluid is extended to a compressible fluid. From hydromagnetic flows in similarity form, it is found that expansion takes place before the reconnection and compression after the reconnection. The pressure gradient in the radial direction causes the field lines to bend into separatrices in the incoming flows. The kinks on the reconnected field lines propagate out as slow-mode hydromagnetic shocks in the outgoing flows. In the expansion phase of the merging the magnetic energy is piled up around the separatrices, and then in the compression phase the energy is converted from magnetic into kinetic and thermal. Subject heading: hydromagnetics