Abstract
A large saddle shaped superconducting magnet was built and tested.
The conductor used was a composite consisting of 0.7cm wide by 0.16cm thick copper strip in which ten Nb-40Zr-10Ti (HISUPER X-alloy) wires were embedded in two rows. The physical characteristics of the magnet were as follows: winding inside diameter, 38cm; winding outside diameter, 88cm; overall length, 180cm. A cryostat to contain the coil had a room temperature space (25cm in diameter) for MHD plasma duct. Outside diameter and depth of the liquid helium vessel were 150cm and 330cm, respectively.
As a result of the test running the following characteristics of the magnet and cryostat were assured.
Test Results Design Values Central field 47kG 45kG Field uniformity 95% >85% Current decay time-constant (persistent mode) >1, 300 hours >720 hours Boil-off rate of liquid helium (with magnet not energized) 10 1/h 11 1/h
