Globally Optimal Algorithm of Superconducting Magnet Design for Gyrotrons

This paper presentsa new hybrid global optimization method to design a 25 T All YBCO solenoid superconducting magnet with a warm-bore diameter of 52 mm for high-frequency gyrotrons in Wuhan National High Magnetic Field Center, China. This method includes 3 main routines: linear programming (LP) code to get the non-rectangular coil design, coil-picking code to get rectangular coil design, and nonlinear programming (NLP) code to get final integer coil design by using rectangular coil design as initial input. The designed magnet includes Inner, Middle and Outer coils which consist of 34, 56 and 68 double pancakes (DP) wound by 4 mm x 0.1 mm bare YBCO tape, respectively. The designed peak-peak field in-homogeneity is 50 ppm within 10 mm Diameter of Spherical Volume (DSV). The designed 5 Gauss line is restricted in a cylinder with the sizes of 10 m in axial direction and 8 m in radial direction, respectively. The maximum hoop stress is limited below 450 MPa. Layer-layer separation happens in the inner coil since non-insulation (NI) winding is adopted. The results show that this methodology is very efficient for High-frequency Gyrotron superconducting magnet design. This methodology also can be used for other solenoid superconducting magnet design, such as Magnetic Resonance Imaging (MRI) superconducting magnet and Nuclear Magnetic Resonance (NMR) superconducting magnet.