High-Speed Shielding Current Analysis in High-Temperature Superconducting Film With Cracks

Two types of numerical methods are proposed for calculating the shielding current density in a high-temperature superconducting (HTS) film containing cracks: differential algebraic equation (DAE) method and virtual-voltage method. A numerical code is developed on the basis of both methods and, by using the code, the performance of both methods is numerically investigated. The results of computations show that, if GMRES is implemented as a linear-system solver, the virtual-voltage method is much faster than the DAE method. In addition, the applicability of the H-matrix method to speedup of the virtual-voltage method is numerically accessed. Consequently, it is found that the acceleration by the 'i-I-matrix method is effective especially for a large-sized shielding current analysis in a high-aspect-ratio HTS film.