Numerical Investigation on Contactless Methods for Identifying Defects in High-Temperature Superconducting Film

Abstract

A numerical method has been developed for analyzing the shielding current density in a high-temperature superconducting (HTS) film containing multiple cracks. By using the method, the inductive method and the scanning permanent magnet method for contactlessly measuring the critical current density has been successfully reproduced, and the identifiability of the multiple cracks in the HTS film has been investigated. The results of computations show that, when the cracks are separated from each other, the multiple cracks can be detected individually in the two types of the contactless method. On the other hand, if the crack is pretty close to the interface, the multiple cracks is considered as a single crack. However, the crack position can be detected collectively. Therefore, the contactless methods is useful method for detecting the multiple cracks in an HTS film.