Superconducting magnet system in a fusion reactor

Okuno, Kiyoshi; Shikov, A.*; Koizumi, Norikiyo

A tokamak fusion reactor requires a superconducting magnet system for plasma confinement and control. Higher magnetic field of the toroidal field (TF) coil can offer better performance of the reactor. Therefore, fusion magnet development always drives a new superconductor to be used in a large magnet on an industrial basis. Magnets for the International Thermonuclear Experimental Reactor (ITER) use NbSn in order to generate a peak magnetic field of 13 T. Technologies for NbSn superconductor has made a significant progress through the extensive development in ITER including the manufacture of the full-scale model coils. A next generation superconductor, NbAl, has outstanding features of large critical current density at the high field. High Tc (Critical Temperature) superconductor (HTS) is another candidate, and if it becomes available, a magnetic filed above 20 T can be realized in fusion reactor. However, technical issues have to be solved for the application of these innovate superconducting materials in Fusion Reactor.