Targets have been developed to measure supersonic radiation transport in aerogel foams using absorption spectroscopy. The target consists of an aerogel foam uniformly doped with either titanium or scandium inserted into an undoped aerogel foam package. This creates a localized doped foam region to provide spatial resolution for the measurement. Development and characterization of the foams is a key challenge in addition to machining and assembling the two foams so they mate without gaps. The foam package is inserted into a beryllium sleeve and mounted on a gold hohlraum. The target is mounted to a holder created using additive manufacturing and mounted on a stalk. The manufacturing of the components, along with assembly and metrology of the target are described here.

In this paper, the opacity of plasma in local thermodynamic equilibrium condition was investigated numerically. The plasma was assumed to be produced by interaction of high power pulse laser with carbon and aluminum. Spectrally resolved opacities under different plasma temperature and density conditions were calculated and radiative absorption due to three absorption mechanisms; inverse bremsstrahlung, photo-ionization, and line absorption in plasmas was studied numerically. The purpose of this study is to calculate the values of absorption for inverse bremsstrahlung and photo-ionization processes for aluminum and carbon plasmas and to compare them for those of cold matter. In this investigation, the influences of density and temperature on plasma absorption were evaluated. The calculation results show that the opacity strength strongly depends on the plasma temperature and density.

In order to realize an effective implosion, the beam illumination non-uniformity and implosion non-uniformity must be suppressed to less than a few percent. In this paper, a direct-indirect mixture implosion mode is proposed and discussed in heavy ion beam (HIB) inertial confinement fusion (HIF) in order to release sufficient fusion energy in a robust manner. On the other hand, the HIB illumination non-uniformity depends strongly on a target displacement (dz) in a reactor. In a direct-driven implosion mode dz of ∼20 μm was tolerance and in an indirect-implosion mode dz of ∼100 μm was allowable. In the direct-indirect mixture mode target, a low-density foam layer is inserted, and radiation is confined in the foam layer. In the foam layer the radiation transport is expected in the lateral direction for the HIB illumination non-uniformity smoothing. Two-dimensional implosion simulations are performed and show that the HIB illumination non-uniformity is well smoothed. The simulation results present that a large pellet displacement of ∼300 μm is tolerable in order to obtain sufficient fusion energy in HIF.

In this article, we study the effect of various parameters on the estimation of radiation temperature inside an indirect drive ICF hohlraum and also study the hydrodynamics of aluminum and gold foils driven by the hohlraum radiation. A multigroup one-dimensional, radiation hydrodynamic code is used for this study. Opacities are calculated using a screened hydrogenic average atom model. We also investigate the opacities of Au-Sm and Au-Gd mixtures. It is shown that the mixing of two high Z materials can lead to an enhancement in the Rosseland means, which is of direct interest in indirect-drive inertial confinement fusion. The radiation temperature inside a cylindrical hohlraum is seen to be strongly dependent on the number of frequency groups used. One group radiation transport underpredicts the radiation temperature. It is shown that erroneous results can be obtained if the space mesh in the hohlraum wall is not fine enough. The spectrum of the radiation inside the hohlraum is seen to be different from Planck, especially in the high-energy range. This may lead to preheating of the target. Hydrodynamics of an aluminum foil driven by the hohlraum radiation is also presented in this article. A scaling law for the radiation-driven shock-wave speed in the gold foil is obtained.