Speaker
Description
The critical properties of REBa2Cu3O7-x (REBCO, RE = Rare Earth) tapes are essential for applications in high-field magnets. Typically, the critical current (Ic) of REBCO tapes is measured under steady-state magnetic fields using direct current (DC). However, at low temperatures, the Ic of these tapes can reach 4 kA, posing significant testing challenges. Recently, a novel approach using pulsed current for Ic measurement has been developed. However, the high current ramp rate (dI/dt) inherent to this method may introduce biases that compromise measurement accuracy. In this study, both DC and pulsed current tests were conducted on REBCO tapes under 77 K self-field and 0–2 T steady-state fields. Simultaneously, a two-dimensional (2D) finite-element model based on the H-formulation was developed to analyze current distribution and energy losses under various magnetic field conditions and current injection. The results demonstrate that the voltage spikes observed during pulsed current injection are primarily due to transient eddy currents in the copper stabilizer layer. This indicates that using pulsed current can not only maintains accurate Ic determination but also offers rapid response and low energy dissipation, providing a theoretical and experimental foundation for evaluating REBCO tape performance under varying magnetic fields.
