Investigation of 15 to 24 MW resistive insert magnets built into a 20 T Ø440 mm room-temperature bore superconducting outsert magnet

Toshihisa Asano, Tsukasa Kiyoshi, Kazuo Watanabe

Research output: Contribution to journalArticlepeer-review


The Tsukuba Magnet Laboratory and the High Field Laboratory for Superconducting Materials collaborated on developing the next-generation 50 T-class hybrid magnet. One of the properties to be incorporated into this next-generation hybrid magnet is energy-saving operation in generating a high-strength magnetic field. This report presents the estimated performance of this hybrid magnet, on the basis of a 20 T Ø440 mm room temperature bore for the superconducting outsert magnet, DC power of 15-24 MW for a three-layered Bitter resistive insert magnet, and a Ø32 mm room-temperature bore for the resistive insert magnet. Cu-Zr (Cu-Ag) alloy is assumed material to be used for the outermost layer (inner two layers) of the Bitter magnet. The estimation indicates that the hybrid magnet generates magnetic fields beyond 47.9 T (49.1 T) for a resistive insert magnet operation power of 15 MW (24 MW) in a 20 T background magnetic field, where the upper-limit design stress on the innermost Bitter coils is tentatively assumed to be 800 MPa. An ultimate tensile strength exceeding 1140 MPa with a conductivity of 72% International Annealed Copper Standard (IACS) for a Cu-Ag alloy plate would be necessary to meet the design stress of 800 MPa. Using this material, we could make the 15 MW water-cooled resistive insert magnet (WM) for this energy-saving, compact hybrid magnet that generates magnetic fields of 47 T and beyond. For a moderated upper-limit design stress of 760 MPa, the corresponding magnetic fields of the hybrid magnet are 47.5 and 48.5 T.

Original languageEnglish
Article number6092447
JournalIEEE Transactions on Applied Superconductivity
Issue number3
Publication statusPublished - 2012


  • Compact hybrid magnet
  • Cu-Ag alloy plate
  • high magnetic field
  • resistive insert magnet

ASJC Scopus subject areas

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


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