This prototype modular coil winding form is the model for 18 winding forms upon which unique, modular electromagnetic coils for the National Compact Stellarator Experiment (NCSX) will be wound. NCSX is an experimental fusion device being constructed at the Princeton Plasma Physics Laboratory and will begin operating in 2009.

NCSX’s modular coils are among the most complex, innovative electromagnets ever designed. The 18 winding forms will consist of non-magnetic stainless steel castings with the winding surfaces machined to a tolerance of plus or minus 0.010 inch. The largest will be 110 inches tall. Each will weigh approximately 6,000 pounds. The prototype modular coil winding form was fabricated to demonstrate that it was possible to pour the modified stainless steel casting (Stellalloy) into the necessary shape and to the desired degree of accuracy. Approximately 25,000 pounds of Stellalloy are used during the pour. This is reduced to less than 6,000 pounds after machining.

The winding forms will provide the backbone of the modular coil system and will be strong enough to support electromagnetic loads in the range of 7,000 pounds per inch. Six identical sets are being manufactured, each comprised of three types of intricately shaped forms. PPPL engineers and technicians are winding layers of insulated copper conductor around the forms to create the modular coils. The electromagnets will help shape the magnetic field confining the NCSX plasma within the vacuum chamber. Plasma is a hot, ionized gas used in the production of fusion energy.