Tore supra - status report concerning the superconducting magnet after the qualifying development program

One of the main features of the medium-size Tokamak, Tore Supra, built in France, relies in its superconducting coils to provide the toroidal magnetic field. This magnet is built with a NbTi conductor inside a Cu-CuNi mixed matrix, cooled by a pressurized superfluid helium bath at 1.8 K and 1 atm. With this original arrangement, high values for the maximum field (9 T), current density and fast varying magnetic field amplitude are simultaneously allowed; this is mainly due to the large heat transfer to the superfluid helium. A description of the superconducting coils and of the associated cryogenic system is presented. Their designs are detailed, after the completion of a 2.5 year program of component development and qualifying tests. 13 refs