HTS-WISE Conductor and Magnet Impregnated with Low-Melting Point Metal

A High-Temperature Superconducting (HTS) conductor and magnet impregnated with low-melting point metal named “WISE” (Wound and Impregnated Stacked Elastic tapes) has been invented. This paper reports results on the first trial of the WISE conductor/magnet and its testing. An HTS solenoid coil without turn-to-turn insulation in accordance with the WISE concept was fabricated and tested. The flexibility of HTS-WISE conductor allowed handmade coil winding. In the first charging test after impregnation, there was no degradation due to thermal contraction. However, it was observed that thermal cycle damaged the HTS tapes after the second cooling. Even with some degradation, the sample achieved a central magnetic field of 0.16 T, having an 800 A current in the steady-state. Despite the appearance of an electric field of ~1 mV/m along the conductor, quench did not occur. In the overcurrent test, self-protection characteristics of a non-insulation coil appeared. These results show that WISE is a smart winding method for making robust HTS coils having even complex 3D shapes.