Computer studies of the three-dimensional magnetic reconnection with the superimposed B-y component

Abstract

Three-dimensional magnetic reconnection is studied using magnetohydrodynamic simulations. The initial configuration is based on the two-dimensional Harris neutral sheet model that lies in the xz plane and is extended in the y direction. Localized anomalous resistivity is applied to the central region, and the subsequent evolution of spontaneous magnetic reconnection is observed. Special attention is given to the results with a finite B-y superimposed on the Harris model. Significant changes are seen in the reconnection morphology, as the B-y component causes asymmetries. The reconnected field lines are skewed, and the plasma flows, shock structures, and current flows show the corresponding peculiar asymmetries. The plasma sheet is also seen twisted. A broader region is affected by magnetic reconnection as B-y increases, and it is seen that energy conversion over the whole simulation domain is more significant when B-y is larger, unless B-y is the dominant component of the magnetic field. The field-aligned component of the current, which initially exists because of the finite B-y component, is enhanced off the central plane when reconnection develops, while it is reduced on the central plane. The spatial scale of resistivity affects the reconnection rate as in previous studies of B-y = 0, yielding a small energy conversion for a very localized model resistivity.