Magnets for the mirror fusion test facility: Testing of the first yin-yang and the design and development of other magnets

Completed in May 1981, the first yin-yang magnet for the tandem Mirror Fusion Test Facility (MFTF-B) at Lawrence Livermere National Laboratory (LLNL) was successfully tested in February 1982 to its full design field (7.68 T) and current (5775 A). Since that time, the entire magnet array has been reconfigured-- from the original A-cell to an axicell design. The MFTF-B magnet array now contains a total of 26 large superconducting coils: 2 sets of yin-yang pairs, 2 sets of transition magnets (each containing two coils), 2 sets of axicell magnets (each containing three coils), and 12 central-cell solenoids. This paper chronicles recent magnet history--from the testing of the initial yin-yang set, through the design of the axicell configuration, to the planned development of the system.