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Using powerful lasers, we are now able to produce in laboratory relevant regimes of density, temperature and velocity to create a diagnosable exact scaled model of magnetic cataclysmic variables accretion column. We present here preliminary results of a numerical modeling of these astrophysical objects which will allow us to precise the experimental setup of future experiments. [ABSTRACT FROM AUTHOR]

This paper deals about pure hydrodynamic and radiation hydrodynamic codes developed at LUTH, dedicated to astrophysical simulations. The studied phenomena in this area are often encountered at high Mach number and in a radiation regime where no a priori assumption can be made on the radiation transfer. The radiative hydrodynamic code HADES has to can perform simulations as well as any optical depths, from smallest to highest. Validation of numerical schemes or physical assumptions will be made by laboratory astrophysical experiments. Therefore a very wide domain of initial conditions has to be accepted for computing. A succinct presentation of three codes is done, accompanied with some astrophysical applications. [ABSTRACT FROM AUTHOR]

In this paper, theoretical and experimental laboratory astrophysics results are presented from the POLAR project, the main focus of which is to design and diagnose an exact scaled accretion column using powerful lasers. These measurements allow the testing of the astrophysical models of accretion processes present in magnetic cataclysmic variables. [ABSTRACT FROM AUTHOR]

Radiative shocks (RS) occur in astrophysical systems and in high-energy density laboratory experiments. Aided by three dimensionless parameters, we propose a classification of RS into four types, integrating previous work that has focused independently on optical depth and on Mach number. Specific terms, such as a cooling function, a radiative flux, or radiative energy and pressure must be added to the Euler equations in order to model these various kinds of shocks. We examine how these terms correspond to the radiative classification regimes. In astrophysics, observed RS arise generally in optically thin material. Thus, radiation escapes without interaction with the surrounding gas, except perhaps to ionize it, and the energy loss in such shocks can be modeled by a cooling function Λ. In this case only the post-shock region is structured by the radiation cooling. We found the analytical solution for hydrodynamic equations including Λ ∝ ρ ε Pζ x θ for arbitrary values of ε, ζ, θ. This is a completely new result. An application of this calculation for the accretion shock in cataclysmic variables of polar type is given in astrophysical terms. We also draw a parallel between RS experiments performed using the LULI2000 laser facility, in France and the Omega laser Facility, in USA. RS developed in these laboratories are more or less optically thick. These high-Mach number RS present a radiative precursor. [ABSTRACT FROM AUTHOR]

We present experiments performed with the LULI2000 nanosecond laser facility. We generated plasma jets by using specific designed target. The main measured quantities related to the jet such as its propagation velocity, temperature and emissive radius evolution are presented. We also performed analytical work, which explains the jet evolution in some cases. [ABSTRACT FROM AUTHOR]

This paper presents some recent measurements on radiative shocks generated in a xenon gas cell using high power laser. We show new results on temperature and electronic density, and on radial expansion of the shock at various initial conditions (laser energy and gas pressure). The data obtained are compared with one-dimensional and two-dimensional hydro simulations. [ABSTRACT FROM AUTHOR]

We present the set-up and the results of a supercritical radiative shock experiment performed with the LULI nanosecond laser facility. Using specific designed targets filled with xenon gaz at low pressure, the propagation of a strong shock with a radiative precursor is evidenced. The main measured quantities related to the shock (electronic density, propagation velocities, temperature, radial dimension) are presented and compared with various numerical simulations. [ABSTRACT FROM AUTHOR]