2025 Volume 20 Article ID: 1405043
Applying high-temperature superconducting (HTS) conductors to the magnets of Helical fusion reactors, which require a higher degree of three-dimensionality compared to the magnets of tokamak devices, can enhance plasma performance by increasing fusion power. By stacking Rare-Earth Barium Copper Oxide (REBCO) tapes, winding them into specific shapes, and then impregnating them with low-melting-point metals, the strain on the tapes can be minimized. Using this method, a 2-m-long U-shaped WISE (Wound and Impregnated Stacked Elastic tapes) conductor was subjected to current testing at temperatures ranging from 6 to 20 K and magnetic fields of 8 T. The conductor had the capability of maintaining 40 kA for 8 s at 6 K, 8 T with an average engineering current density of 31 A/mm2, without a temperature rise or quench. Repeated tests at 20 K and 8 T with a maximum current of 22 kA showed no temperature increase, confirming the conductor’s mechanical robustness. In the preliminary stages of the energization test, an increase in voltage reminiscent of a quench was observed, even though the current was lower than the critical current value. However, this voltage was suppressed as the maximum value decreased with each repetition of energization. Such behavior is considered similar to a training effect and indicates the movement of REBCO tape inside the conductor.
