Optimization of isotope composition of fusion plasmas

Journal article, 2011

The radial profiles of deuteron and triton densities in a fusion tokamak reactor are computed by taking into account anomalous transport due to ion temperature gradient and trapped electron drift instabilities in the plasma core and neoclassical transport in plateau-banana regimes, residual anomalous diffusion and convection triggered by edge localized modes in the edge transport barrier. The charged particle sources due to influx of neutral particles through the separatrix and ablation of frozen pellets in the plasma interior are optimized by searching for conditions providing the minimal outflow of unburned tritons to divertor target plates and their exhaust by pumping systems. It is demonstrated that such conditions correspond to fuelling of deuterium plasma component with gas puffing and of tritium with pellets and a ratio of deuteron/triton densities close to 2/1 at the separatrix. Effects of the absolute level and the ion mass dependence of neoclassical and anomalous transport contributions, of the position where neutrals enter the confined volume through the separatrix on the radial profiles of the ion densities are investigated.