Jeremy Weiss1 2 Danko van der Laan2 1 Dustin McRae1 U. Trociewitz3 Dmytro Abraimov3 Xinbo Hu3 David Larbalestier3 Chul Kim4 Sastry Pamidi4 Xiaorong Wang5 Hugh Higley5 Soren Prestemon5 Ramesh Gupta6 Tim Mulder7 8 Herman ten Kate7 8

1, University of Colorado Boulder, Boulder, Colorado, United States
2, Advanced Conductor Technologies, Boulder, Colorado, United States
3, National High Magnetic Field Laboratory, Tallahassee, Florida, United States
4, Center for Advanced Power Systems, FSU, Tallahassee, Florida, United States
5, Lawrence Berkeley National Laboratory, Berkeley, California, United States
6, Brookhaven National Laboratory, Upton, New York, United States
7, CERN, Geneve, , Switzerland
8, University of Twente, Enschede, , Netherlands

It’s been over 30 years since the discovery of high-temperature superconductivity, but the finicky intrinsic properties of these game-changing materials have required countless scientists and engineers to hone into a form that can now be applied as a true conductor technology on a macroscopic scale. Coated conductors, in which ReBCO thin films are deposited on a technical substrate utilizing a number of complex industrial processes, are finally becoming available from several vendors in long-lengths at costs that are likely to decrease in the coming years. The form-factor of coated conductors, an anisotropic tape with a high aspect-ratio, still presents a challenge in terms of cabling and winding into practical magnet systems. Studies on the strain-state within the ReBCO layer as a function of bending led to the development of the Conductor-on-Round-Core (CORC®) concept, in which several ReBCO coated conductors are wound helically around a relatively small former. These round, isotropic, HTS conductors offer a wide variety of operating currents and current densities to suit a range of applications. CORC® cables with thickness of 5 to 8 mm have been developed for power transmission and for use in large magnets, that require only very limited bending of the cable, or bundled into 6-around-1 cable in conduit conductors (CICC) for fusion and detector magnets. Much more flexible CORC® magnet wires with thickness of 2 to 4 mm are being developed for solenoids and accelerator magnets that require a current density (Je) of at least 300-600 A/mm2 at 20 T. An overview of the current status and future developments of CORC® cables and wires is presented here with an emphasis on conductor processing and application.

This work was in part supported by the US Department of Energy under agreement numbers DE-SC0007891, DE-SC0007660, DE-SC0009545, DE-SC0014009 and DE-SC0015775 and the U.S. Navy under contract numbers N00024-14-C-4065 and N00024-16-P-4071