Blast Wave Measurements of ICF Hohlraum Energy Loss at Z

Summary form only given. The Z dynamic hohlraum (DH) was used to examine several inertial confinement fusion problems including radiation transport. In these experiments, a copper-walled hohlraum is mounted above the DH to capture ~100 kJ of axially-emitted quasi-Planckian radiation (T_rad ~ 180-220 eV). A 1-mm diameter hole was placed at the top of the hohlraum, while on a fraction of targets a 400-micron wide groove was also cut in the side. A cylinder of 60 mg/cc silica aerogel foam surrounds the hohlraum to provide a media in which blast waves (BW) will form out the top and sides of the hohlraum. Single shot soft x-ray imaging using the high-resolution, 6.151 keV monochromatic imager system [Sinars et al, 2004] recorded the formation of BWs out the holes of the hohlraum as well as wall ablation and motion. This experiment diagnosed energy loss through holes similar to diagnostic and/or laser entrance holes in hohlraums by measuring the distance that the BWs traveled in the foam shell. We discuss the experiment design, results, and comparison to 2D radiation hydrodynamic simulations.