Evaluation of Magnetic-Field Distribution by Screening Current in Multiple REBCO Coils

In a superconducting coil using a REBCO tape, a large screening current is induced by the magnetic field perpendicular to the tape. The irregular magnetic field generated by this screening current affects the magnetic-field distribution in high-field magnet applications, which require a magnetic field with high accuracy and temporal stability. Therefore, in these applications of the REBCO coil, we have to investigate and suppress the influence of the screening current in the REBCO tapes. In this study, we carried out experiments and numerical simulations focusing on the irregular magnetic field generated by the screening currents in multiple-REBCO-coil models assuming real operations in magnetic applications such as NMR/MRI system. The results of the numerical simulation are in good agreement with the behaviors of the screening field observed in the experimental results. In addition, we discussed the differences in the screening field for various excitation conditions using the numerical results of the current distribution in the coil.