Magnetic Island Formation in Coexisting System of Resonant Magnetic Perturbation and Perturbed Bootstrap Current

摘要

A reduced two-fluid model describing the coexisting system of the resonant magnetic perturbations (RMPs) and plasma flows is extended to include an effect of the perturbed bootstrap current. Using the extended model, nonlinear formation mechanisms of magnetic islands, such as the neoclassical tearing mode (NTM) triggered by the RMP penetration, and the RMP penetration process in the presence of the perturbed bootstrap current, can be consistently discussed. In numerical simulations, it is revealed that the necessary seed island to trigger the NTM is smaller when it is generated by the RMP penetration, meaning the RMP penetration can be an efficient NTM triggering mechanism.