Effect of conducting vacuum chamber on the compression along the major radius of a tokamak plasma column

The paper considers the effect of a thin conducting vacuum chamber on the movement of the plasma column in a tokamak during plasma compression in the direction of the major radius. It is shown that a sort of frictional force acts on the plasma column from the direction of the vacuum chamber. The maximum value of this force per unit length can be considerable: Fmax J2/(ac2 ), where J is the plasma current and a is the distance from the plasma centre to the side wall of the chamber. A study of the dynamics of the plasma column motion shows that in the presence of a vacuum chamber the displacement velocity of the column is bounded by the value V* c2/(2 ???), where ? is the thickness and ? the conductivity of the chamber wall. If the velocity rises above the critical value, the compression is accompanied by the development of self-oscillations.