Design and test of a compact twisted stacked YBCO cable for fusion application

To meet the application requirements of high magnetic field and high current in future fusion magnet systems, a compact twisted stacked tape cable with high current density is proposed. Three stepped grooves are evenly distributed around a circular former, and a 20+10 superconducting tapes configuration is arranged in each single groove. The performance of the cable under self-field is investigated through simulation modeling and experiment on a 1-meter sample. Firstly, the electromagnetic and mechanical properties of cables are studied through simulation. According to the simulation results, the prospective critical current reaches 5090 A under self-field at 77 K while the maximum von Mises stress and volumetric strain obtained from the simulation during the current-carrying process are within acceptable ranges. A sample with a twist pitch of 300 mm is fabricated, consisting of 18 superconducting tapes and 72 copper tapes. The measured and simulated results of the critical current of this sample are 1900 A and 1970 A respectively, with a deviation of 3.5 percent. The feasibility of the proposed cable has been preliminarily demonstrated through these experimental and simulation results. Subsequent research will be conducted on the optimization of cable parameters, including geometric dimensions and tape capacity, to achieve better performance.