The effect of a strong unstable vertical magnetic field in the vorticity column. The field is added at t = 200. At first, the effect of the field is to stabilize the elliptic turbulence, which is seen in the subsequent snapshots. The disappearance of the vortex at later times is caused by the development of a strong channel flow that stretches the column and destroys its vertical coherence. If the initial vertical field is stable, the strength of the channel does not grow and the vortex survives indefinitely.