Operating Characteristics of a 1.5-MJ Pulsed Superconducting Coil

The ohmic heating coils of tokamak fusion reactors require a stored energy on the order of 1 GJ, a ramping rate of ~9 T/s, and a peak operation current of 50 to approximately 100 kA. Owing to power balance requirements of the reactors at these sizes, only superconducting coils are expected to be economical. For the development of the ohmic heating coils, a cryostable pulsed superconducting coil has been constructed and tested at Argonne National Laboratory. The coil has a stored energy of 1.5 MJ and a peak field of 4.5 T with a peak operation current of 11.2 kA. The coil was tested with both dc and pulsed currents.