Successful operation of the Nb3Sn Swiss insert coil for the 12 tesla Sultan test facility

The design and fabrication principles of the first high-field insert for SULTAN are described and the results of the coil test performed in the background field of the SULTAN facility are presented. The Swiss Nb₃Sn insert coil is the first of three A15 coils of SULTAN planned to demonstrate the feasibility of high-current, high-field superconductor technology for fusion devices in Europe. The forced-flow, steel-reinforced conductor is based on an external diffusion Nb₃Sn cable, and is reacted before conventional fabrication of the 60-cm bore coil. During tests in the background field of SULTAN, the coil reached the design current of 6 kA without training. It could only be turned normal by raising the temperature to 7.8 K at a current of 6.5 kA. In the present single-insert configuration of SULTAN a peak conductor field of 10.5 T was reached.