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

Three-dimensional magnetic reconnection is studied using magnetohydrodynami c simulations. The initial configuration is based on the two-dimensional Ha rris neutral sheet model that lies in the xz plane and is extended in the y direction. Localized anomalous resistivity is applied to the central regio n, and the subsequent evolution of spontaneous magnetic reconnection is obs erved. Special attention is given to the results with a finite B-y superimp osed 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 incr eases, and it is seen that energy conversion over the whole simulation doma in is more significant when B-y is larger, unless B-y is the dominant compo nent of the magnetic field. The field-aligned component of the current, whi ch initially exists because of the finite B-y component, is enhanced off th e central plane when reconnection develops, while it is reduced on the cent ral plane. The spatial scale of resistivity affects the reconnection rate a s in previous studies of B-y = 0, yielding a small energy conversion for a very localized model resistivity.