  The different behaviours of deuterium (D) and tritium (T) in the hot spot of
marginally-igniting cryogenic DT inertial-confinement fusion (ICF) targets are
investigated with an ion Fokker-Planck model. With respect to an equivalent
single-species model, a higher density and a higher temperature are found for T
in the stagnation phase of the target implosion. In addition, the stagnating
hot spot is found to be less dense but hotter than in the single-species case.
As a result, the fusion reaction yield in the hot spot is significantly
increased. Fusion neutron diagnostics of the implosion find a larger ion
temperature as deduced from DT reactions than from DD reactions, in good
agreement with NIF experimental results. ICF target designs should thus
definitely take ion-kinetic effects into account.
