Design analysis of a solid nitrogen cooled "permanent" high-temperature superconducting magnet system

Benjamin J. Haid, Haigun Lee, Yukikazu Iwasa, Sang Soo Oh, Young Kil Kwon, Kang Sik Ryu

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


Potential performance advantages of a solid nitrogen cooled "permanent" high-temperature superconducting (SN2/HTS) magnet system over a liquid helium cooled low-temperature superconducting (LHe/LTS) system are explored. The SN2/HTS system design includes a second solid heat capacitor that cools a radiation shield. Recooling of the heat capacitors is performed with a demountable cryocooler. The SN2/HTS system offers both enhanced stability and improved portability over a LHe/LTS system. Design codes are constructed to compare the SN2/HTS system design with a LHe/LTS design for a general permanent superconducting magnet system employing a room temperature bore. The codes predict the system volume and mass that should be expected for a given set of design requirements, i.e. field strength and bore size, and a given set of conductor properties. The results indicate that present HTS conductor critical current and index are not yet sufficient for producing SN2/HTS systems of a size that is comparable with that expected for a LHe/LTS system; however, the conductor properties of Bi2223/Ag have been consistently improving, and new HTS conductors are expected to be developed in the near future. The codes are used to determine the minimum Bi2223/Ag conductor performance required for a SN2/HTS system to be competitive with a LHe/LTS system.

Original languageEnglish
Pages (from-to)617-634
Number of pages18
Issue number10
Publication statusPublished - 2002 Oct
Externally publishedYes

Bibliographical note

Funding Information:
Work supported in part by the Korea Electrotechnology Research Institute and Daesung Cable Co., Korea.


  • HTS magnet
  • Persistent mode
  • Solid nitrogen

ASJC Scopus subject areas

  • General Materials Science
  • General Physics and Astronomy


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