High-Speed Method for Analyzing Shielding Current Density in High-Temperature Superconductor

A fast method is proposed for calculating the shielding current density in a high-temperature superconductor. When the power law is assumed as the constitutive relation linking the shielding current density and the electric field, the initial-boundary-value problem for the shielding current density cannot be always solved with the Runge-Kutta method. This is the case even when an adaptive step-size control algorithm is incorporated. In order to overcome this difficulty, the constitutive relation is modified for a large value of the shielding current density. By using this method, a numerical code is developed for calculating the shielding current density. The results of computations show that the proposed method is much faster than the conventional implicit one for a large-scale problem.