HINT modeling of three-dimensional tokamaks with resonant magnetic perturbation
In order to consider the nonlinear 3D equilibrium response of the resonant magnetic perturbations field, the nonlinear three-dimensional (3D) equilibrium is discussed for the 3D perturbed tokamak. To model the magnetic topology, a nonlinear 3D equilibrium calculation code, which has been developing in stellarator researches, is applied to the perturbed tokamak. That code does not assume the existence of perfectly nested flux surfaces. In the nonlinear 3D equilibrium calculation, the change of the magnetic topology due to the nonlinear 3D equilibrium response, which is a lowest order plasma response appearing in the 3D steady state. The parallel current flow along perturbed field lines three-dimensionally drives the perturbed field to break the magnetic topology. This effect is significant along the separatrix and must be considered to interpret the experimental observations.