Simulation of Contactless Crack Detection in HTS Films: Application of H-Matrix Method to Fast Matrix-Vector Multiplication

Abstract

Detectability of the multiple cracks in a high-temperature superconducting (HTS) film by a scanning permanent magnet method has been investigated numerically. To this end, a numerical code has been developed for performing a shielding current analysis in an HTS film with cracks. Furthermore, the GMRES(k) method and the H-matrix method are adopted in the code. By using the code, the scanning permanent magnet method can be simulated successfully. The results of the computations show that the x-coordinate of the crack endpoint cannot be estimated with increasing the magnet radius. On the other hand, the y-coordinate of the crack endpoint can be detected accurately.