ATF superconductor and coil design characteristics

A study was initiated to look into the possibility of building a novel superconducting Advanced Toroidal Facility (ATF) magnet system. The system would operate initially at liquid nitrogen temperature as a pulsed system. At the time of the study, a modular torsatron-type magnet system was being considered. A superconducting coil built with a copper-jacketed Internally Cooled Superconductor (ICS) can produce an ATF coil with high current densities at high fields. A geodesic method of winding is described that can make the winding of the complex-shaped coils more feasible than the older, conventional methods. With this geodesic winding, the conductor can be pulled with tension, and thus elaborate clamps are not needed to prevent sideward slipping or bunching of the conductors. The bobbin can be machined on numerically controlled machines having several axes of movement. A preliminary simulation test indicates that initial pulse operation of these coils at liquid nitrogen temperature is feasible. Pulse operation at half the superconducting design field (B /SUB M/ = 5.0 T) can be sustained for more than 4 s without excessive temperature and pressure rise