A gradient coil design for a high-temperature superconducting bulk magnet using the finite-difference method

摘要

The screening current induced in a bulk superconductor presents a critical problem for gradient coil design because it gives rise to undesirable effects on the gradient field: namely, a decrease in the efficiency and a distortion of the field. In this paper, a new coil design method for the bulk magnet is proposed using the finite-difference method (FDM) and the target-field method. The calculation using the FDM was implemented with the boundary conditions of the bulk magnet. Transverse and longitudinal coils were designed and fabricated for a high-temperature superconducting bulk magnet. The calculated results of the efficiency and the nonlinearity distribution of the gradient field agreed well with the measured results.