The ITER magnet system

The main components of the ITER magnet system include 20 toroidal field (TF) coils, a central solenoid (CS), seven poloidal field (PF) coils and structural elements. The TF coils operate at a maximum field of 12.5 T with a total stored energy of about 100 GJ. These coils are enclosed in stainless steel cases that form the major part of an integrated mechanical structure and are bucked on the CS. The CS provides about 140 MA turns at a maximum field of 13 T. In the reference design, the CS is a monolithic, 12 m tall coil. An alternative segmented CS design is being considered to extend the range of operational flexibility and plasma control capability. The PF coil system comprises seven coils, with diameters up to 30 m, for plasma and shape control. The salient activity of the ITER R&D programme is the manufacture of model coils. The conductor production for these coils is well underway and construction of the coils has started. The initiation of the model coil test programme is scheduled for mid 1998.