Radiation hydrodynamics simulations of low-z foams heated by z-pinch radiation

Summary form only given, as follows. The z-pinch dynamic hohlraum ICF concept implodes a capsule embedded in a 5-10 mg/cc CH foam. The foam is located at the center of an annular z-pinch such that the pinch implosion onto the foam creates a radiation wave that drives the capsule. Understanding the details of the radiation transport in these foams is critical for successful ICF. We are designing experiments with foam samples placed externally to the z-pinch in order to study details of the radiation heating. Spectroscopic measurements of embedded mid-Z tracers are the principle diagnostics of the foam temperature. We describe integrated computer simulations used to design these experiments. VisRad view-factor simulations used to calculate various components of the bulk z-pinch spectral distribution as well as the geometry induced gradients in the drive flux along the sample surface are presented and discussed. The foam response (i.e., temperature and density) to the calculated drive history is computed in 1-D with the BUCKY radiation hydrodynamics code and compared for multi-group diffusion and multi-angle radiation transport algorithms over a wide range of foam thicknesses and densities. In addition, analysis of the thermodynamic equilibrium between the mid-Z tracer layers and the surrounding foam medium is presented with a discussion on implications for absorption spectroscopy experiments on the Z machine.