Species separation and modification of neutron diagnostics in inertial-confinement fusion

Abstract

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