60 R-1

A full set of twelve internal coils and related magnetic sensors are now operational in the DIII-D tokamak. The design requirements for the new coil system was to maximize the magnetic field at the plasma edge, operate with a frequency range of dc to 1000 Hz, and fit behind the existing graphite wall tiles. The coil design adopted and installed is a water-cooled hollow copper conductor insulated with polyamide and housed inside a stainless steel tube that forms a vacuum boundary. The coil is rigidly mounted to the inside of the vacuum vessel.the vessel mid-plane. The coils are single turn with a conductor length of 5 m and an area of 1 m sq. In order to minimize error fields and electromagnetic forces, the radially oriented power and cooling water feeds are coaxial. The coils are shielded from the plasma by the plasma facing graphite tiles.