High Temperature Superconducting (HTS) Coils for a Compact Spherical Tokamak

High temperature superconductors (HTSs) have the potential to impact the future development of superconducting applications for research magnets in physical sciences and industrial products. A compact spherical tokamak of major radius 25 cm has been designed and engineered using the second generation HTS material, REBCO tapes. It was developed with the primary objective to test out the feasibility of a fully superconducting device made entirely from HTS materials and hence be the first tokamak to demonstrate the practicality of this new medium operating at temperatures above 4.2 K. The tokamak has 6-D shaped toroidal field coils, and two poloidal field coils, each of which is wound in a pancake geometry. Each coil is made in one continuous winding and the coils are assembled together. Results of initial coils and magnet cooling and energisation will be presented.