Vertical stability analysis in tokamaks using the variational method

A variational method is described for determining the increment of increasing and shifting an ideal magnetohydrodynamic plasma with arbitrary shape in the presence of an arbitrary system of conductors with a finite conductivity and feedback circuits. A simplified version of the method was included as a module in the TEQ code for calculation of the equilibrium of a free boundary plasma in axisymmetric tokamaks with the one- and two-zero divertor. The code was used when designing the TPX and ITER devices