Loss of alpha particles during slowing-down in an axisymmetric tokamak reactor

The containment properties of alpha particles during the slowing-down process in an axisymmetric tokamak reactor are studied by using Monte-Carlo calculations, in which the pitch-anglescattering effects are included. The loss of alpha particles during slowing-down is found to be safely negligible in a pure DT plasma, but increases proportionally to the effective charge number of the plasma and cannot be ignored in a highly contaminated plasma (Z eff > 4), compared with the loss of 3.5-MeV particles.