Superconducting magnet system for high power gyrotron

A superconducting magnet system was designed and fabricated for a 1-MW gyrotron in a frequency range of 110-140 GHz. The system consists of superconducting magnets, a cryostat, a two-stage cooler, and power supplies. The diameter of the gyrotron bore is 220 mm. A magnetic field of 5.0 T in the resonance region was obtained with a 340-mm bore superconducting split coil. A magnetic field of 0.25 T in the gun region was obtained with two solenoid coils. A persistent current switch, removable current leads, and a two-stage cooler were adopted to decrease the heat load of liquid helium. The superconducting magnet system has successfully achieved a 110% rated current without quenching.<>