Left column shows the results from the asymmetric reconnection, while the right column shows the results from the symmetric reconnection. Color codings in panels (a) and (b) represent B_z, and the superposed black contours are magnetic field lines. The red curves denote the B_x = 0 surface. Panels (c) and (d) show the profiles of B_z along x across the center of the RF at five different instants. The curves in panel (c) are taken at z = 30.10, 30.01, 30.80, 29.93, 29.66d_i, respectively, due to the weak vertical motion of the B_x = 0 surface in the Z direction, while all the curves in panel (d) are along z = 15d_i.