GENERATION OF FIELD-ALIGNED CURRENTS AND ALFVEN WAVES BY 3D MAGNETIC RECONNECTION

We have carried out a three-dimensional compressible MHD simulation to study the generation of field-aligned currents (FAC's) and Alfven waves by magnetic reconnection for locally antiparallel magnetic fields across the current sheet. Reconnection is triggered by a localized resistivity. The results indicate that both FAC's and Alfven waves are generated by the three-dimensional reconnection process. Two pairs of FAC's are generated on each side of current sheet. The polarities of the resulting FAC pair in the leading bulge region are opposite to those of a FAC pair in the trailing quasi-steady region. It is further found that a large portion of the FAC's (similar to 40%) is located in the closed field line region. We examine the Walen relation between FAC and parallel vorticity and find that Alfven waves are generated and propagate away from the reconnection site. We discuss the relevance of our results to the observed Region 1 FAC's at noon.