Numerical simulation of inductive method for measuring critical current density of HTS bulk

✍ Scribed by A. Kamitani; T. Takayama; S. Ikuno

• Publisher: Elsevier Science
• Year: 2008
• Tongue: English
• Weight: 366 KB
• Volume: 468
• Category: Article
• ISSN: 0921-4534
• DOI: 10.1016/j.physc.2008.05.061

✦ Synopsis

The inductive method for measuring the critical current density in a high-temperature superconducting (HTS) bulk has been investigated numerically. In the method, an ac current is applied in a small coil placed just above a HTS bulk and, simultaneously, the third-harmonic voltage V 3 induced in the coil is measured. In order to evaluate V 3 , a numerical code has been developed for solving the initial-boundary-value problem of the shielding current density. As the J-E constitutive relation, the power law is assumed. By using the code, V 3 is calculated as a function of the coil current. The results of computations show that, for the case with a sufficiently weak coil current, there is direct proportionality between the square root of V 3 and the coil current. In addition, it is found that the proportional relationship fades out gradually with a further increase in the coil current until the magnetic shielding is broken down behind the bulk.