Loss Measurement in a Cryogen-Free Bi-2223 HTS Dipole Magnet for Beam Line Switching

Jun Yoshida, Takaaki Morie, Atsushi Hashimoto, Hitoshi Mitsubori, Yukio Mikami, Keiichi Watazawa, Kichiji Hatanaka, Hiroshi Ueda, Mitsuhiro Fukuda, Tetsuhiko Yorita

Research output: Contribution to journalArticle

Abstract

High-temperature superconducting (HTS) magnets have several advantages for ac and pulse operation due to having a high critical temperature. However, fast magnetic field changes generate severe ac losses and eddy current losses. Therefore, loss estimation and reduction is a significant issue for HTS magnet cooling design. For future cooling design, we have measured losses of a Bi-2223 HTS magnet for beamline switching in the cyclotron facility at the Research Center of Nuclear Physics, Osaka University. The time-varying magnetic field losses for triangular wave excitation with a perpendicular magnetic field amplitude of 0.8 T in wire and a minimum period of 42 s were obtained from measured cryocooler temperatures and preliminary measured cooling capacity curve. The eddy current losses of the metal components were calculated using transient electromagnetic finite element analysis. The ac losses of the Bi-2223 wire were derived from the measured time-varying magnetic field losses and the calculated eddy current losses. The frequency dependence of their losses indicates the importance of accurate evaluation and reduction of the eddy current losses for the future magnet with higher charging speed.

Original languageEnglish
Article number7819541
JournalIEEE Transactions on Applied Superconductivity
Volume27
Issue number4
DOIs
Publication statusPublished - Jun 1 2017

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Keywords

  • ac losses
  • Bi-2223 tape
  • high-temperature superconductors
  • HTS coils
  • Superconducting magnets

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering

Cite this

Yoshida, J., Morie, T., Hashimoto, A., Mitsubori, H., Mikami, Y., Watazawa, K., Hatanaka, K., Ueda, H., Fukuda, M., & Yorita, T. (2017). Loss Measurement in a Cryogen-Free Bi-2223 HTS Dipole Magnet for Beam Line Switching. IEEE Transactions on Applied Superconductivity, 27(4), [7819541]. https://doi.org/10.1109/TASC.2017.2653222