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Hydrodynamic experiments have become a very active area within High Energy Density Laboratory Astrophysics. In such experiments, preheat of an interior surface due to heating prior to shock arrival can alter the initial conditions for further evolution and can change the nature of the experiment (Olson et al., 2003). Unfortunately, preheat cannot typically be detected without undertaking dedicated...
Recent results from an ongoing series of Rayleigh-Taylor instability experiments being conducted on the Omega Laser are described. The goal of these experiments is to study, in a controlled laboratory setting, the mixing that occurs at an unstable interface subjected to an acceleration history similar to the explosion phase of a core-collapse supernova. In a supernova, the Reynolds number characterizing...
A series of experiments is underway using the Omega laser to examine radiative shocks of astrophysical relevance. In these experiments, the laser accelerates a thin layer of low-Z material, which drives a strong shock into xenon gas. One-dimensional numerical simulations using the HYADES radiation hydrodynamics code predict that radiation cooling will cause the shocked xenon to collapse spatially,...
In recent years, we have carried out experiments at the University of Rochester’s Omega laser in which supersonic, dense-plasma jets are formed by the interaction of strong shocks in a complex target assembly (Foster et al., Phys. Plasmas9 (2002) 2251). We describe recent, significant extensions to this work, in which we consider scaling of the experiment, the transition to turbulence,...
We review the experimental design and results from recent radiative shock experiments at the Omega Laser facility. Using a beryllium pusher to drive a shock in excess of 100 km/s in a xenon-filled shock tube creates a system where the density and temperature structure are significantly affected by radiation transport from the shock-heated matter. To measure this system with high accuracy, streaked...
The paper discusses experiments, modeling, and uncertainty assessment radiative shocks produced by using high-power lasers to launch a thin Be plate into Xe gas at >100 km/s.
Summary form only given: Radiative shocks are shock waves whose structure has been altered by radiation transport from the shock-heated matter. Such shocks are present in numerous astrophysical systems, including supernova remnants, supernovae, and accretion disks. Recent experiments have used the Omega laser to study radiative shock systems that are optically thin upstream and optically thick downstream...
Summary form only given. Shear flows arise in many high-energy-density (HED) and astrophysical systems, yet few laboratory experiments have been carried out to study their evolution in these extreme environments. Fundamentally, shear flows can initiate mixing via the Kelvin-Helmholtz (KH) instability and may eventually drive a transition to turbulence. We present two dedicated shear flow experiments...
Shock waves driven above a threshold velocity near 100 km/s become strongly radiative, converting most of the incoming energy flux into radiation. We produce such shock waves in Xe or Ar by using a laser to shock, ionize, and accelerate a Be plate into a gas-filled shock tube. Structure develops in these systems due to both radiative energy transfer and hydrodynamic instability. We are conducting...
The Center for Radiative Shock Hydrodynamics (CRASH) at the University of Michigan is a focused effort to do predictive science in the regime of radiative hydrodynamics. The current plan with CRASH is to use 2D HYADES (or H2D) to model the laser-energy-deposition portion of the experiment, before passing the results to the CRASH code to be used as its initial conditions. HYADES is a Lagrangian Radiation...
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...
Summary form only given. Our goal is to experimentally confirm or disprove the hypothesis that the Rayleigh-Taylor instability could be responsible for the observed transport of heavy elements from the core of SN1897A, a core-collapse supernova, into its outer layers. Observational astrophysicists have been unable to explain the X-ray or luminosity data from SN1987A. Strong hydrodynamic instabilities...
Summary form only given. Microchannel plates (MCPs) are used in a variety of imaging systems as a means of amplifying the incident radiation. Using a microchannel plate mount recently developed at the University of Michigan, the effects of a metal reflecting grid are explored. Employing the reflecting grid, we create a potential difference above the MCP input surface that forces ejected electrons...
Summary form only given. Microchannel plates (MCPs) are an essential component in an imaging diagnostic known as an X-ray framing camera, which is used extensively to image the plasma produced by radiation imploded targets at facilities such as NIF, Nike, Omega, and Z. An MCP is used to convert incident X-ray photons into electrons with gains of the order 102 to 104. These electrons are then accelerated...
Summary form only given. We have seen a sequence of recent experiments aimed at producing and studying radiative shocks. These experiments are opening the door to fundamental radiation hydrodynamic studies using laboratory tools. To complement such experiments, the author has done theoretical work, introducing new solution approaches that allow more complete treatment of some simple cases and providing...
Summary form only given. Our group has been studying radiative shocks using laser targets that contain a gas, most often xenon. Our motivation includes the production of conditions in the laboratory relevant to astrophysical phenomena and astrophysical simulation codes. A specific phenomenon of interest is the production of a dense, collapsed layer in a given material. Past experiments have consisted...
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