Can the shape of the cathode be changed to improve the performance of the plasma? What if the ends of the cathodes were elongated beyond the end of the anode and curved in towards the anode like a 90 degree fish hook? What if the fish hooks were slightly twisted away from the axis of the anode? The curve should allow the pinch current to approach closer to the center of the pinch and the twist would give the plasma a definite spin. If the cathodes are adjustable, the amount of spin can be mechanically controlled and would override any residual magnetic field in the chamber. Refer to the possible benefits in this report:
More on Magnetic Fields