EPEIUS: Physics and engineering studies of a small aspect-ratio tokamak-torsatron hybrid

Studies for a planned small aspect-ratio tokamak-torsatron hybrid, based on a concept developed at the Oak Ridge National Laboratory, are presented. A device of 0.5 m major radius and toroidal field on axis of 1 T is considered with up to 1 MW of auxiliary heating and 200 kA of toroidal current. Vacuum toroidal field configurations and MHD equilibria with and without plasma current are found. Transport estimates indicate that such a device will operate as a torsatron in the electron 1/nu, neoclassical regime with 0.5 MW of electron heating alone, and in the Vv regime of both species if an additional 0.5 MW of ion heating is added. An experimental program to study transport and disruptions, and to assess the effects of plasma current and both naturally occurring and induced radial electric fields is outlined. A preliminary engineering design is briefly described.