THE ROLES OF ADVECTION AND DIFFUSION IN PLANAR MAGNETIC MERGING SOLUTIONS

Since cosmic plasmas are highly conducting, large-scale magnetic field s are tied almost completely to the velocity field of the fluid. Only in localized regions of strong current density can the magnetic held s lip through the plasma, allowing magnetic energy to be converted into ohmic heating or the kinetic energy of mass motion. Here we contrast t he roles of advection and resistive diffusion in three different stead y-state two-dimensional models for magnetic energy conversion: magneti c annihilation, reconnective diffusion and a kinematic model based on the classical magnetic reconnection picture. First we examine the diag nostic of 'field-line slippage' and show that it provides a useful ind icator of the relative importance of advection and diffusion in each s olution. We then quantify the energy release characteristics of the di fferent models by examining the ratio of ohmic heat to kinetic energy generation.