High performance method for determination of shielding current density in HTS plate

The numerical method for determining the shielding current density in the high-Tc superconducting plate is investigated. After being discretized by means of the finite element method and the backward Euler method, the governing equation of the shielding current density is reduced to the nonlinear system. If the B dependence of the flow resistivity and the critical current density is neglected, the nonlinear system is easily solved by use of the deaccelerated Newton method (DNM). Once their B dependence is taken into consideration, a decrease in the relaxation factor will not always improve the convergence behavior of the DNM. In order to resolve this difficulty, the DNM has been modified so that the relaxation factor can be chosen adaptively. The results of computations show that the CPU time required for the modified method is about 1/21 times as much as that for the DNM.