Design of a Resistive Insert for a 45 T Hybrid Magnet

The Tsukuba Magnet Laboratory (TML) and the High Field Laboratory for Superconducting Materials collaborated on the design study of a 50 T-class hybrid magnet. The highest fields of the hybrid magnet were examined with the existing 15 MW DC source at the TML used for the resistive insert magnet. The strength of the Cu-Ag wire exceeds 1400 MPa in ultimate tensile strength (UTS). Several upper-design stresses corresponding to the Cu-Ag wire strength were placed on Bitter disks to evaluate the resistive insert. The design was conducted with two inner radii, 29 mm and 19 mm. Resistive insert magnets are consist of three-layered coaxial Bitter coils operated with the 20 T outer superconducting magnet with a room temperature bore of 400 mm. In this hybrid magnet, a UTS of 1200 MPa is needed for the Bitter disks of the resistive insert to generate 46 T.