Collapsing radiative shock measurements in xenon on the omega laser

Abstract

Summary form only given. Radiative shocks occur in many high-energy density explosions, but prove difficult to create in laboratory experiments or to fully model with astrophysical codes. Here we describe an experiment significant to astrophysical shocks, which produces a driven, quasi-planar radiative shock in xenon gas at 6 mg/cc. A thin, low-Z disk is driven into a cylindrical volume of xenon gas via laser ablation pressure. This impact creates a shock in xenon, after which the disk travels behind the shock providing a continuing pressure source. With average shock speeds above 100 km/sec, this shock can radiate away energy just behind the shock front, creating a thin layer of dense xenon. Simulations suggest this material is compressed an order of magnitude more than strong shock relations would predict. X-ray backlighting techniques have yielded images of a collapsed shock compressed to <1/25 its initial thickness (45 mum) at a speed of ~100 km/s when the shock has traveled 1.3 mm. Optical depth before and behind the shock is important for comparison to astrophysical systems, where low densities combined with powerful explosions provide ideal conditions for producing radiative shocks