Design and R&D for the liquid nitrogen cooled poloidal field coil system for the Compact Ignition Tokamak (CIT)

The Compact Ignition Tokamak requires a liquid-nitrogen-cooled, pulsed poloidal field coil system for plasma heating, shaping, and control. It will dissipate about 1780 MJ in a total pulse length of 22 s and will require a peak power of 390 MW. The central solenoid will have a bore diameter of 0.68 m, a height of 2.4 m, and a central field of almost 22 T. Geometric restrictions are such that an aggressive structural concept is required; hence, the coil consists of a stack of explosively bonded copper/steel plates. Each plate is cut into eight turns by a water-jet cutting process. Features of the design and selected results from an R&D (research and development) program which is underway are reviewed.<>