Permeation of the vertical magnetic field through the thin shell in a Tokamak

Effects of the resistivity and the transeverse cuts of a shell on the equilibrium position of a plasma column in a Tokamak is considered. The equations for the permeation of the vertical component of the magnetic field due to the shifted current with respect to the shell and the leakage field from the iron core of a transformer through the shell are derived with the approximation of a thin shell and a short gap. Comparison with the model experiment using a current-carrying conductor in the 1/5 device of JFT-2 apparatus is satisfactory. A formula for the displacement of the plasma is also shown.