Magnetic shielding analysis of high-Tc superconducting plates by power law, flux-flow, and flux-creep models

The magnetic shielding performance of a high-T_c superconducting (HTS) plate is investigated numerically. By taking account of the crystallographic anisotropy in the shielding current density of the melt-powder-melt-growth YBa₂Cu₃O_x plate, the multiple-layer structure is introduced to modelize the HTS plate. In this case, the shielding current density is governed by the integral-differential equation of the scalar potential. In addition, the power law is used as the J-E constitutive equation for description of the characteristics of the Type-II superconductor. When the equation is descretized by using the finite element method and the weighted average method, the resulting algebraic equation is solved by using the decelerated Newton method. A numerical code for analyzing the time evolution of the shielding current density has been developed and, by use of the code, the shielding performance of HTS plates is investigated. In addition, the results obtained by using the power law, the flux-flow and the flux-creep models are compared.