3-D field analysis of a superconducting bulk magnet

Magnetic field can be trapped in a superconducting bulk by using the field cooling method. In this paper, trapped field was calculated by 3-D numerical analysis. The existing 1-D critical state model was expanded to 3-D. With this model and iteration method, the nonlinearity of J-E constitutive relation of a superconducting bulk was numerically modeled. The field cooling system with a hexahedral bulk and cylindrical magnet, which is impossible to be analyzed by 2-D or axisymmetric numerical analysis, was analyzed by the presented method. Being compared with experimental data, the validity of the presented method was verified. The finite element method was adopted for numerical calculation.