Radiative shocks: New results for laboratory astrophysics

Abstract

In the framework of the Laboratory Astrophysics, we present new radiative shocks experiments performed using the LULI2000 facility. A strong shock is driven in a multi-layered solid target (CH-Ti-CH) which accelerates into a gas cell (∼ 60 km/s) filled with Xenon at low pressure (0.1 - 0.3 bar) and produces a radiative supercritical shock [4, 8]. A low power laser beam (8 ns - 532 nm) probes the Xenon gas in the transverse direction and is injected into a VISAR and on two optical framing cameras (GOI). These diagnostics allow to determine electron density variation, to measure both precursor and shock velocities along the shock propagation axis [3, 5] as well as the 2D shape of the shock. On rear side, the light emitted from the shocked Xenon is imaged onto the slit of a streak camera. An absolute calibration of the optical system allows to determine the brightness temperature [8]. Data were obtained for different laser intensities and gas pressures. Two VISARs on rear side allowed an accurate measurement of the shock conditions in the pusher before the breakout in the Xenon. Comparison between I D (MULTI) and 2D (DUED [1, 2]) radiative hydrodynamic codes and measured quantities (shock velocity, shape, radial expansion, and temperature as well as precursor velocity and precursor electron density) are presented.