Laser-driven shock waves for the study of extreme matter states

Abstract

During the last ten years, the ability of high power lasers to generate high energy density shocks has made them a reliable tool to study extreme states of matter. These states of matter are relevant in many important physics areas such as astrophysics, planetology and ICF physics. Here, we present some representative studies performed by using a driven laser shock: melting of iron at pressures relevant for geophysics, developments of new techniques to measure the density of highly compressed matter and a study of a radiative shock.

In situlattice measurement of the bcc phase boundary in Mg on the principal shock Hugoniot

“…Shock-loading [17][18][19] is of particular interest in the study of the hcp to bcc phase transition in Mg as the desired pressure (and temperature) regime can be easily accessed and characterized with traditional velocimetry techniques [20]. In addition, the shock itself provides a fiducial for measuring time-dependent processes in the lattice, thus yielding important information on the kinetics of the phase transition during dynamic loading.…”

Highly efficient, easily spectrally tunable X-ray backlighting for the study of extreme matter states

“…With our scheme, it is possible to reach a higher spatial resolution (10 mm) in the shock wave direction. Moreover, as the X-ray image is monochromatic, the mass density measurement of shocked plastic can be deduced with limited error bars (Benuzzi-Mounaix, 2006. These rear side diagnostics provided the shock velocity and the temperature.…”

“…Recently, several experiments using two-dimensional (2D) point projection method have been performed to radiograph a shock compressed target, either using thermal X-rays (Miyanaga et al, 1983;Marshall & Su, 1995;Stoekl et al, 2008) or K a emission (Benuzzi-Mounaix et al, 2006;Ravasio et al, 2008). Here, the main issues to infer density were the lack of monochromacity and the source size.…”

“…The results are encouraging but it remains technically difficult to produce bright X-ray point sources in order to reach the desired spatial resolution. As an alternative of X-ray point projection diagnostics, X-ray monochromatic backlighting imaging using spherically bent crystals is successfully applied nowadays (Belyaev et al, 1976;Pikuz et al, 1995Pikuz et al, , 1997Aglitskiy et al, 1998Aglitskiy et al, , 1999Koch et al, 1998Koch et al, , 1999Fraenkel et al, 1999;Workman et al, 1999;Sanchez del Rio et al, 1997;Sinars et al, 2003aSinars et al, , 2003bCuneo et al, 2005;Benuzzi-Mounaix et al, 2006;Le Pape et al, 2008). It has already been experimentally demonstrated that in the case of almost normal incidence in backlighting traditional scheme, spatial resolution around 1.6 mm could be reached within a field of view about1 mm (Aglitskiy et al, 1998) and about 10 mm within a bigger field of view (4 Â 20 mm 2 ) (Sinars et al, 2003a(Sinars et al, , 2003b.…”

Density measurement of shock compressed foam using two-dimensional x-ray radiography

“…Only a few experiments have been carried out to study foam EOS and opacities. 4,5 The impedance mismatch technique has been used in foam EOS experiments. In this technique, the determination of only the velocity of the shock leads to a large error in the determination of the density as a consequence of error amplification through the Rankine-Hugoniot equations.…”