INERTIAL CONFINEMENT FUSION USING HOHLRAUM RADIATION GENERATED BY HEAVY-ION CLUSTERS

This paper discusses the feasibility of employing heavy-ion cluster be ams to generate thermal radiation that can be used to drive inertial f usion capsules. The low charge-to-mass ratio of a cluster may allow th e driver beam to be focused to a very small spot size with a radius of the order of 100 mu m, while the low energy per nucleon (of the order of 10 keV) may lead to a very short range of the driver particles in the converter material. This would result in high specific power depos ition that may lead to a very high conversion efficiency. The problem of cluster stopping in cold matter, as well as in hot dense plasmas ha s been thoroughly investigated. The conversion efficiency of cluster i ons using a low-density gold converter has also been calculated over a wide range of parameters including converter density, converter geome try, and specific power deposition. These calculations have been carri ed out using a one-dimensional hydrodynamic computer code that include s a multigroup radiation transport scheme [Ramis et al., Comput. Phys. Commun. 49, 475 (1988)]. The problem of symmetrization of this radiat ion field in a hohlraum with solid gold walls has also been thoroughly investigated using a three-dimensional view factor code. The characte ristics of the radiation held obtained by this study are used as input to capsule implosion calculations that are done with a three-temperat ure radiation-hydrodynamic computer code MEDUSA-KAT [Tahir er al., J. Appl. Phys. 60, 898 (1986)]. A reactor-size capsule which contains 5 m g deuterium-tritium (DT) fuel is used in these calculations. The probl em of using a fuel mixture with a substantially reduced tritium conten t has also been discussed. (C) 1997 American Institute of Physics.