Influence of B-dependence of critical current density on magnetic shielding performance of MPMG-YBCO plate

The magnetic shielding performance of the MPMG-YBCO plate is investigated numerically by assuming the flux-flow and flux-creep model as the J-E constitutive relation. The magnetic-field dependence of the critical current density and the flow resistivity is also taken into consideration through the Kim model and the Bardeen-Stephan model. Under these assumptions, the damping coefficients and the shielding factors are calculated as functions of the frequency and the amplitude of the applied AC magnetic field. The results of computations show that an increase in the frequency will enhance the shielding performance of the MPMC-YBCO plate. In addition, there exists the lowest limit of the frequency, above which the shielding performance is saturated, and the limit increases with the amplitude of the applied magnetic field. Furthermore, it turns out that the magnetic shielding performance is hardly influenced by the magnetic-field dependence of the critical current density.