Grant: Strategic Projects - Group

The fuels for fusion reactors (deuterium and tritium) are in gaseous state at room temperature and cannot be stored in a fusion reactor. Fusion fuels thus have to be continuosly fed externally as in automobile fuel injection. In large fusion reactors in the future, the exiting fueling technologies (e.g., ice pellet injection) may not be adequate particularly if direct fueling at the plasma core is required. Fusion reactions are most active at the core where both plasma temperature and density are high. Core fueling will have another important advantage. In burning tokamak plasma, a large fraction of palsma current is self-driven as the boot strap current which sensitively depends on the radial plasma pressure profile. Optimization of the bootstrap current requires active control of plasma pressure profile which can only be achieved by control of fueling. Compact torus (CT) is a fully ionized high density plasmoid confined by the magnetic field produced by itself. Once detached from the formation electrodes, CT can be accelerated to a large velocity (200 to 400 km/sec) which allows penetration into a strong magnetic field. The attractiveness of CT injection as a fueling means has been recognized for some time particularly in Canada where pioneering work was done on development of CT gun and the first disruption free injection experiment in a tokamak. In this application, funding is requested for further development of the CT technology in the Plasma Physics Laboratory, University of Saskatchewan, where STOR-M, the only active Canadian tokamak, exists. Fueling technology for fusion reactors must meet stringent restrictions including small density perturbation and capability to control the local plasma pressure gradient in the core for the purpose of bootstrap current optimization. CT injection has a potential to meet the requirements and will help realization of steady state tokamak fusion reactors.