Application of Superconductors to Center Conductor of Spherical Tokamak Reactor

Abstract

The feasibility of superconducting center conductors in spherical tokamaks has been studied. The advantage of superconducting center conductors is evaluated from the view point of loss reduction, increasing q and reduction of required βp-The magnetic field dependence of the critical current density is taken into account. The center conductor is divided radially into several layers, and the operating current density of each layer is optimized. If A_??_1.3 and β_??_0.6, the electric power loss can be reduced by the application of superconducting center conductors where, κ-3 and q-10. In spherical tokamak reactors with low electric power loss, larger q can be attained by the application of superconducting center conductor. In other word, the βp required for the specified q can be reduced.