Enhancement of High-Frequency Magnetic Field Generation of In-Vessel Coils Using High Permeability Inserts

Dynamic resonant magnetic perturbation coils operating at a frequency of up to several kilohertz are installed on tokamaks to investigate plasma response. A large amount of eddy current will be induced in the conductor, resulting in a strong attenuation of the magnetic field of the coils. Thus, to reduce the screening effect of the eddy current on the magnetic field, the insertion of soft magnetic material blocks with high permeability between coils and the conductor is proposed. Experiments were conducted to verify the proposal, and the preliminary results indicate that the magnetic field generated by the coils after the insertion of magnetic material blocks can be approximately two times larger than that without blocks.