Development and Performance of 65 T Fast-cooling User Magnet With Long Service Life

Since the accomplishment of the pulsed magnetic field facility at the Wuhan National High Magnetic Field Center in 2013, five 65 T monolithic-coil magnets have been developed and used for scientific research. As the workhorse, the 65 T user magnets show excellent cooling performance and long service life. These user magnets have typical bore size of 21 and 23 mm. For electrical transport measurements, the magnets are energized by a 2 or 3-MJ capacitor bank with crowbar circuit for ~40-70 ms pulse duration. For magnetization measurements, shorter pulse duration of 11 ms for a field waveform with almost symmetrical rising and falling edges can be obtained with a 1.25-MJ capacitor bank that allows high-voltage reversal. The cooling time between two 60 T pulses ranges from 30 to 50 min depending on the magnets and the field waveform. Up to now, three of these magnets failed after 916, 583, and 947 pulses with the magnetic field above 60 T. The other two have delivered 706 and 56 pulses above 60 T and are still in operation.