Plasma Response to Complex External Magnetic Perturbations

The dependence of the plasma response to external magnetic perturbations consisting of an unknown intrinsic external error field and a known and controlled applied external field is studied theoretically by constructing various response models. For a rotating dissipative plasma, the plasma behaves nearly ideally in the linear regime. The response is relatively weak for a low beta plasma. In the quasi-linear regime, the response connects to the development of magnetic islands within the plasma. The relationship of the modeled response to that observed in DIII-D is studied. Possibility of application of this model in determination of intrinsic error field in ITER is explored.