Trapped Field Characteristic of YBCO Bulk in AC External Magnetic Field

Hiroshi Ueda, Atsushi Ishiyama, Tohru Morisaki

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Trapped field characteristics are one of the key factors in the application of high-temperature superconducting bulk, such as magnetic levitation systems, motors, bulk magnets and so on. The immutable trapped field is required in superconducting bulk applications as a quasi-permanent magnet, however, the trapped field is influenced and changed by a time-varying external magnetic field in a realistic operational environment of electrical devices. This means that shielding current distribution within the bulk is changed by the time-varying magnetic field and the transient magnetic flux movement results in temperature rise and finally reduction of the trapped field. In this study, we observed the abrupt reduction of the trapped field for the external AC magnetic field in the range of frequency up to 50 Hz. And we also performed the numerical simulation using a newly developed computer program based on the finite element method (FEM). In the simulation program, the voltage-current (E–J) characteristics, which depend on the irreversibility temperature are taken into account. From these results, it can be considered that the abrupt reduction of the trapped field is caused by the temperature rise due to AC loss.

Original languageEnglish
Pages (from-to)1357-1364
Number of pages8
JournalIEEJ Transactions on Power and Energy
Issue number11
Publication statusPublished - 2004
Externally publishedYes


  • finite element method
  • high-temperature bulk superconductor
  • trapped field attenuation

ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Electrical and Electronic Engineering


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