How well do we understand magnetic reconnection?

The present status of the theory of magnetic reconnection is reviewed. Quasi-Alfvenic processes arise, when the mechanism for magnetic diffusion is localized around the X-point. This is shown in the simple model of resistive MHD with artificially localized resistivity (it is well known that a uniform resistivity distribution leads to a macro-current sheet and slow reconnection dynamics). When collisionless effects dominate characterized by certain intrinsic plasma scale-lengths, localization comes about through the dispersion of hydromagnetic waves at wavelengths below these scales. As a consequence fast reconnection should be possible under most plasma conditions. Most of the energy released by reconnection is predicted to go into ion bulk motion, though the details of energy partition between ions and electrons and of the efficiency of suprathermal particle production are still under investigation. While energetic electrons may be generated by the runaway effect in the diffusion region, any super-Alfvenic ions seem to be due to some mechanism not related directly to the reconnection process.