Test Operations of the Upgraded Hybrid Magnet at CHMFL

High Magnetic Field Laboratory of Chinese Academy of Sciences (CHMFL) has upgraded the 40 T hybrid magnet built in October 2016. The latest test operation of the upgraded CHMFL hybrid magnet was completed in August 2022, and the maximum central field arrived at 45.22 T in the center of a 32 mm clear bore, which is the highest steady magnetic field by user magnet in the world. The upgraded hybrid magnet consists of a Florida-Bitter resistive magnet producing 34.22 T central field and a superconducting magnet producing 11 T central field and providing a room-temperature bore of 800 mm. The enhanced performance of the upgraded CHMFL hybrid magnet is mainly attributed to the new design of the resistive insert coils, and the outer superconducting magnet still generated steadily a central field of 11 T without change. This article mainly describes the commissioning and test operating results of the upgraded CHMFL hybrid magnet.