Critical Current Measurement Over Full-Width HTS Tapes Under Flat-top Pulsed Magnetic Field Up to 38.7 T

One key element in designing coils using High Temperature Superconducting (HTS) ReBCO (Rare earth BaCuO) tapes as the base material is the critical current (Ic). Beyond the magnetic fields available in DC magnets, there is a lack of practical data on the magnetic field dependence ofIc. However, several world-class projects are currently aiming to develop high field user magnets using HTS tapes in the 30 T-40 T range. We propose combining a flat-top pulsed magnet with a rapidIcmeasurement system to access the critical current across full-width HTS tapes in this high-field regime. A dedicated plastic-based probe was developed and tested under different magnetic field strengths and temperatures. To withstand the mechanical stress resulting from strong Lorentz forces and enable variable temperature operation, the HTS tape was immersed at room temperature into mineral oil and subsequently fixed by the oil solidification upon cooling. The critical current of a full-width HTS ReBCO tape was successfully measured under a magnetic field of 38.7 T at 26 K. Temperature monitoring was necessary to account for the temperature rise caused by eddy currents in the normal-conducting layers of the HTS tape.