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Numerical Investigations on Detectability of Crack by Contactless j_C-Measurement Method

Teruou TAKAYAMA, Atsushi KAMITANI and Hiroaki NAKAMURA¹⁾

Yamagata University, 4-3-16 Johnan, Yonezawa, Yamagata 992-8510, Japan

1)

National Institute for Fusion Science, 322-6 Oroshi-cho, Toki 509-5292, Japan

(Received 7 December 2012 / Accepted 22 February 2013 / Published 23 April 2013)

Abstract

The inductive method for measuring the critical current density j_C and detecting the crack in a high-temperature superconducting (HTS) film have been investigated numerically. To this end, a numerical code has been developed for analyzing the shielding current density in the film with a crack. The results of computations show that the accuracy of the inductive method is degraded remarkably due to the crack. Specifically, it is found that, if the orthographic projection of the coil overlaps with the crack, the value of measured j_C decreases. This is mainly because the spatial distribution of the shielding current density becomes asymmetry. In conclusion, the crack size and position can be accurately detected by measuring the j_C-distribution in the HTS film.

Copyright (c) 2013 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

critical current density, crack detection, high-temperature superconductor, inductive method, numerical simulation

DOI: 10.1585/pfr.8.2401025

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References

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This paper may be cited as follows:

Teruou TAKAYAMA, Atsushi KAMITANI and Hiroaki NAKAMURA, Plasma Fusion Res. 8, 2401025 (2013).