Confinement of Alpha Particles in Low-Aspect-Ratio Deuterium-Tritium Ignited Tokamaks

The effect of reducing the aspect ratio on the confinement of deuterium-tritium fusion products, i.e., alpha particles, in tokamaks is discussed. It is shown that for low-aspect-ratio tokamak reactors, the alpha-particle heating efficiency can be similar to conventional tokamaks; at the same time, the alpha-particle confinement time can be much shorter than that of conventional tokamaks. Thus, one can facilitate alpha-particle ash removal while maintaining high alpha-particle heating efficiency by reducing the aspect ratio.