Suppression of the magnetic surface shift by plasma rotation in a tokamak

The equilibrium of a toroidally rotating plasma in an axisymmetric tokamak-like system is considered. The equilibrium equation is represented in the form of the Grad-Shafranov equation in which, in contrast to the static case (with no plasma rotation), the plasma pressure depends on both the flux surface label and major radius. It is shown that the dependence of the pressure on the major radius makes it possible to choose the profile of the plasma rotation velocity so as to minimize the effect of the plasma pressure on the shift of the flux surfaces, in which case it might be anticipated that the maximum pressure of the confined plasma will be higher. This result was derived analytically and tested numerically for a number of typical tokamak configurations with a fixed plasma boundary.