Development and performance of a 2.9 Tesla dipole magnet using high-temperature superconducting CORC(R) wires

Although the high-temperature superconducting (HTS) REBa2Cu3Ox (REBCO, RE-rare earth elements) material has a strong potential to enable dipole magnetic fields above 20 T in future circular particle colliders, the magnet and conductor technology needs to be developed. As part of an ongoing development to address this need, here we report on our CORC(R) canted cos magnet called C2 with a target dipole field of 3 T in a 65 mm aperture. The magnet was wound with 70 m of 3.8 mm diameter CORC(R) wire on machined metal mandrels. The wire had 30 commercial REBCO tapes from SuperPower Inc. each 2 mm wide with a 30 mu m thick substrate. The magnet generated a peak dipole field of 2.91 T at 6.290 kA, 4.2 K. The magnet could be consistently driven into the flux-flow regime with reproducible voltage rise at an engineering current density between 400-550 A mm(-2), allowing reliable quench detection and magnet protection. The C2 magnet represents another successful step towards the development of high-field accelerator magnet and CORC(R) conductor technologies. The test results highlighted two development needs: continue improving the performance and flexibility of CORC(R) wires and develop the capability to identify locations of first onset of flux-flow voltage.