Critical current distribution prediction in REBCO coated conductors via magnetization field and electromagnetic inversion

Accurate prediction of the critical current ( I c ) is essential for understanding the operating mechanisms and engineering applications of Rare-earth Barium Copper Oxide (REBCO) coated conductor (CC) tapes. I c uniformity in these tapes is typically characterized using magnetic field measurements, performed either under an applied external field or after magnetization. The combined effect of the background magnetic field and the screening-current self-field reduces the current in the tape to a value below the self-field critical current ( I c 0 ). Furthermore, magnetic relaxation following magnetization negatively affects the accuracy of I c 0 evaluation. Existing calibration models that relate magnetic field to I c 0 are predominantly empirical and rely on external methods such as the four-probe technique for parameterization. This study proposes a novel I c 0 prediction model that uses magnetic measurement data and electromagnetic inversion while fully accounting for magnetic field and relaxation effects. The method was validated through numerical simulations and experiments. Results show that it can accurately predict I c 0 values for both flawless and defective tapes during and after magnetization. Additionally, the method successfully identifies defects and reveals their influence on current distribution. This approach shows promise for application in reel-to-reel processes, enabling accurate I c 0 prediction in long-length REBCO tapes.