Compact Design of a 30 T Superconducting Magnet Incorporating YBa2Cu3O7Coated Conductor Tapes and Pre-reacted Nb3Sn Strand Cables

We set out to design as compactly as possible a 30 T superconducting magnet consisting of an YBa2Cu3O7 (Y123) insert coil and a CuNb-reinforced Nb3Sn (CuNb/Nb3Sn) background coil. The engineering current density Je for an Y123-coated conductor tape is larger at 14–15 T and 4.2 K than that for a CuNb/Nb3Sn strand. Adopting Y123-coated conductor tapes in the high field region above 14–15 T proves highly effective for the fabrication of a very compact 30 T superconducting magnet. A 30 T, 52 mm-room-temperature bore superconducting magnet can be constructed in the coil grading of a 16 T Y123 insert and a 14 T CuNb/Nb3Sn background coil, and the stored magnetic energy of 32 MJ successfully lies in the 1/3 level in comparison with the 30 T nuclear-magnetic-resonance (NMR) superconducting magnet reported previously.