Magnetization in ReBCO-Based CORC Cables in Magnetic Fields up to 30 T for Accelerator Applications

This study presents experimental measurements of the magnetization of ReBCO CORC cables in magnetic fields up to 30 T at 4.2 K. Such data are relevant for accelerator, fusion, and other potential applications. The cable was comprised of 29 ReBCO tapes, with a cable OD of 3.63 mm and cable pitch of 7.16 mm. The tapes were 2 mm wide, had a substrate thickness of 30 µm, and a Cu plating thickness of 5 µm. The cable had an ${I}_{\mathrm{c}}$ of 1675 A at 77 K and self-field. The CORC cable was received from Lawrence Berkeley National Laboratory (LBNL) with ID 170131-Berkeley. We used a susceptibility technique, with the NHMFL's Bitter (resistive) magnet acting as the primary coil. We constructed a sample holder with a pick-up coil (secondary) as well as a compensation coil. The CORC cables were measured first as a single and then a three-stack CORC, placed with the field perpendicular to the conductor length. Magnetization (M) versus applied magnetic field (μ₀H) was measured for field sweeps with amplitudes up to ± 30 T. Additionally, “accelerator-like” magnetic cycles were performed. Here, the field, initially at some low (1 T) “injection” field was increased to the maximum (“collision”) field, ramped back to some hold field near zero (${B}_{\mathrm{h}}$), and then increased to the nominal injection field again, mimicking operational conditions relevant to particle accelerators. The magnetization at injection (taken here as 1 T) was observed to be ≅ 1100 kA/m. Furthermore, the penetration field (${B}_{\mathrm{p}}$), which defines the point at which flux reaches the center of the conductor, was found to increase from 1.2 to 2 T when we moved from a single-stack to a three-stack of cables. These measurements are important for understanding the CORC cable's implementation in high-field applications such as particle accelerators.