High temperature superconducting YBCO insert for 25 T full superconducting magnet

A 25 T superconducting magnet with a 10 T YBCO high temperature superconducting (HTS) insert and a 15 T low temperature superconducting (LTS) (Nb₃Sn and NbTi) outsert is fabricated. To design the superconducting magnet system, an optimal design software which combined the advantages of global optimization and local optimization has been proposed to study the number and type of coils to affect the final optimal results, and some important characteristics, for example, coil hoop stress and operating margin and quench characteristics are studied. The high temperature superconductor YBCO inserts with the inner diameter of 41 mm, the height of 115 mm, and outer diameter of 124 mm have been designed and fabricated with the operating temperature at 4.2 K. The outserts of NbTi and Nb₃Sn with the inner diameter, outer diameter and height of 180.22, 443, and 400.5 mm, respectively, have been fabricated and tested. It reaches to the operating magnetic field at 15 T. The combined HTS and LTS coils can generate a central field of 25 T at 4.2 K. In this paper, the 25 T superconducting magnet with LTS and HTS coils are reported.