A review article: Compact magnetic field generators containing HTS bulk magnets cooled by refrigerators and their feasible applications

Tetsuo Oka, Jun Ogawa, Satoshi Fukui, Takao Sato, Tomohito Nakano, Kazuya Yokoyama, Takashi Nakamura, Hiroyuki Fujishiro, Koshichi Noto

Research output: Chapter in Book/Report/Conference proceedingChapter

1 Citation (Scopus)


Various types of strong magnetic field generators with use of HTS bulk magnets and the small-scale refrigerators have been actually proposed and experimentally estimated for the feasible applications. The most characteristic feature of bulk magnets is regarded as compact and strong field generators with respect to their magnetic field spaces or their machine structures of themselves. Among them, the magnetic flux density of the face-toface magnetic poles reached 3.2 T and 4.4 T when they were activated by the pulsed field magnetization and the field cooling method, respectively. Furthermore, a very small bulk magnet generating 2.8 T and the system featured by the wide magnetic poles containing seven magnets have been constructed with use of ST pulse tube coolers in order to expand the feasible application areas. On the other hand, although the bulk magnets are characterized by their steep field distributions, we attempted to gain the uniform magnetic field space, and successfully achieved the uniformity of 385 ppm in 4 mm range by combining the deformed magnetic field profiles which generated between the face-to-face magnetic poles. The performances of these unique systems have exceeded those of the conventional electromagnet or any permanent magnets by far, demonstrating the superiority to other strong magnetic field generators.

Original languageEnglish
Title of host publicationHigh-Temperature Superconductors
Subtitle of host publicationOccurrence, Synthesis and Applications
PublisherNova Science Publishers, Inc.
Number of pages16
ISBN (Electronic)9781536133424
ISBN (Print)9781536133417
Publication statusPublished - 2018 Jan 1
Externally publishedYes



  • Bulk magnet
  • High temperature superconductor
  • Magnetic field trapping
  • Pulsed field
  • Refrigerator

ASJC Scopus subject areas

  • Engineering(all)
  • Materials Science(all)

Cite this

Oka, T., Ogawa, J., Fukui, S., Sato, T., Nakano, T., Yokoyama, K., Nakamura, T., Fujishiro, H., & Noto, K. (2018). A review article: Compact magnetic field generators containing HTS bulk magnets cooled by refrigerators and their feasible applications. In High-Temperature Superconductors: Occurrence, Synthesis and Applications (pp. 291-306). Nova Science Publishers, Inc..