Full-process fabrication and validation of a 16 m TSTC-CICC conductor for compact fusion magnets

Abstract This paper presents the full-process fabrication and validation of a 16 m-long, six-slot REBCO twisted stacked-tape cable-in-conduit conductor (TSTC-CICC), a significant step toward compact, high-field fusion magnets. The conductor design incorporates a copper core with helical slots containing stacks of REBCO tapes, with vacuum pressure impregnation (VPI) of solder employed to achieve superior structural integrity and electrical stabilization. Characterization at 77 K demonstrated excellent longitudinal uniformity (maximum deviation 5%) in critical current and an average n -value of 15, indicating no performance degradation from the bending and impregnation processes. Experimental data were used to validate a finite-element H-formulation model, which subsequently predicts an engineering current density of 228.387 A mm − 2 at 80 kA under operational conditions of 20 K and 20 T. These findings confirm the viability of both the proposed TSTC-CICC architecture and the VPI process for long-length high-temperature superconducting conductors, thereby underpinning their future engineering application in next-generation fusion devices.