Critical Current Correlations and Regressions Across the Superconducting Parameter Space of REBCO Wires, B||c

Commonwealth Fusion Systems (CFS) is pursuing the high-field approach to fusion energy, enabled by magnets composed of 4 mm 2G REBCO wire. Most of these magnets will operate in the high field (20 T) and low temperature (∼20 K) regime and therefore require characterization of the critical current at those parameters. The industry standard is to use (77 K, self-field) data for rapid characterization of critical current. However, Ic (77 K, SF) is a poor predictor of performance at high (>6 T) field, low temperature applications, and so more predictive correlations are extremely desirable. This study examines critical current correlations between high temperature (44–77 K) with low field (0–5 T) and low temperatures (20 K) with high field (6–20 T) from multiple manufacturers. Employing these correlations will allow for the use of cheaper and simpler critical current test systems that can still accurately predict high field, low temperature performance. Moreover, they will provide higher confidence in the predicted performance of magnets. This paper presents the predictive ability of these correlations and the associated error analysis.