We have qualitative observations of large poloidal and toroidal nonuniformities in the currents generated in the resistive wall. The electric field set up by the decaying plasma current, in conjunction with the eddy currents generated by the motion of the plasma column, leads to a very large poloidal nonuniformity in the toroidal component of the wall current, with a possible reversal of the current near the strike point. A more quantitative characterization of these processes and an extension of the work to single-null geometry are under way. Significance Loss of vertical stability, due to a disruption or a failure in the feedback system, is an event that probably cannot be completely avoided in the operation of a tokamak. Thus, a quantitative understanding of the currents generated by a VDE and the electromagnetic forces generated by them on the conducting structures around the plasma column is essential for the design and operation of the next generation of tokamaks.
Horizontal axis is the toroidal angle.
Poloidal angle, measured from the outboard midplane, is on the vertical axis.