Snapshots of the unstable flux rope in Run T1 visualized by rainbow-colored field lines. Green field lines are started at the z-axis (with uniform spacing) to visualize the overlying flux and the vertical current sheet that forms under the rising flux rope. Pink field lines visualize the ambient flux in the vicinity of the flux rope, which recloses after the eruption. The magnetogram, B_z(x, y, 0), is shown in gray scale; a logarithmic scaling is used because the sunspot flux is rather concentrated due to the small value of d.