Reconnection theory in three dimensions

Abstract

One of the most interesting aspects of magnetic reconnection theory in three-dimensions, as opposed to two, is that electric fields are generated with a component parallel to the magnetic field. When the magnetic field has null points, the parallel electric field occurs on the separator field line joining the null points, but if null points are absent, then the region of parallel electric field typically extends over a much broader region. The exact distribution of the parallel electric field is determined by the way the plasma flow drives the reconnection. Topologically, there are two basic types of reconnection, known as spine reconnection and fan reconnection, but it is not yet clear how these two types are related to actual reconnection processes occurring in the Sun. Several important advances have been made recently in applying reconnection theory to three-dimensional configurations such as flares and X-ray bright points where magnetic reconnection is thought to be important. However, our knowledge of the generation of electric fields in these configurations still remains incomplete, and this makes it difficult to understand the relationship between magnetic reconnection and the acceleration of energetic particles.