WB6-1-INV

Recent progress on CORC® cable, wire and high-field insert magnet development

Dec.3 08:30-08:50 (Tokyo Time)

*Danko van der Laan1, Jeremy Weiss1, Ulf Trociewitz2, Dima Abraimov2, Ashleigh Francis2, Daniel Davis2, Youngjae Kim2, Huub Weijers2, Lance Cooley2, David Larbalestier2, Drew Hazelton3, Xiaorong Wang4

Advanced Conductor Technologies LLC, Boulder, Colorado 80301, U.S.A. and University of Colorado, Boulder, CO 80309, U.S.A.1

National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, U.S.A2

SuperPower Inc., Glenville NY, 12302, U.S.A.3

Lawrence Berkeley National Laboratory, Berkeley, California 94720, U.S.A.4

Advanced Conductor Technologies is developing HTS Conductor on Round Core (CORC®) cables and wires for use in high-field magnets, as well as the magnet technology that warrants successful operation of such magnets. An overview of the current status of the CORC® wire development is presented in which the next generation of CORC® wires wound from SuperPower’s REBCO tapes with 25 μm substrates have achieved an engineering current density of over 450 A/mm2 and a critical current exceeding 4 kA at 20 T. The next generation of CORC® wires will become readily available in the coming years once REBCO tapes with these thin substrates transition into standard production at SuperPower.

CORC® wires have been successfully incorporated into prototype canted-cosine-theta (CCT) magnets that would ultimately generate a dipole field of 20 T in combination with a low-temperature superconducting outsert. The successful test of a stand-alone, 4-layer CCT magnet that generated a dipole field of 2.9 T is highlighted, while the design of a 5 T stand-alone magnet to be manufactured in 2021 will be provided.

To demonstrate the maturity of CORC® cables for use in high-field magnets, a CORC® cable insert solenoid was developed and successfully tested in a 14 T background magnetic field. The CORC® cable solenoid was designed to operate at high current, high current density, and high hoop stress; a combination that is essential in the development of low-inductance high-field cable magnets. The 4-layer 45-turn CORC® insert magnet demonstrated highly stable operation even within the flux flow regime. It demonstrated a critical current of 4,404 A in a 14 T background field, resulting in a combined central magnetic field of 15.86 T and a peak magnetic field on the conductor of 16.77 T, which is about 86 % of the expected performance based on single-tape measurements. The CORC® insert solenoid was the first HTS magnet operating in a high background magnetic field at currents of several kA. The results show the benefits of multi-tape magnet cables, such as CORC® cables over single-tape magnet conductors for use in high-field magnets. Current sharing between tapes in CORC® cables suppresses hot spot development at local tape defects, allowing for highly stable magnet operation at high current densities up to the critical current of the conductor.