Design of rotating resonant magnetic perturbation coil system in the STOR-M tokamak

The interaction between resonant magnetic perturbations (RMP) and plasma is an active topic in fusion energy research. RMP involves the use of radial magnetic fields generated by external coils installed on a tokamak device. The resonant interaction between the plasma and the RMP field has many favorable effects such as suppression of instabilities and, under certain conditions, improvement of discharge parameters in tokamaks. The RMP technique has been successfully implemented in the STOR-M tokamak. A set of (m = 2, n = 1) helical coils carrying a current pulse was used to study the effects of RMP on magnetic islands, plasma rotation, and other edge plasma parameters. A new RMP system is being developed for the STOR-M tokamak. The system consists of a number of external saddle coils distributed in the poloidal and toroidal directions and powered by AC power supplies to generate a rotating RMP field. Numerical simulations have been carried out to calculate several parameters for the new RMP system such as the magnetic field and the dominant modes generated by the coils. The dominant mode generated by the new RMP coil system may be tuned to (2, 1) with significant contributions from (2, 3) and (2, 5) modes.