Experimental study of radiative shocks at PALS facility

Abstract

We report on the investigation of strong radiative shocks generated with the high energy, sub-nanosecond iodine laser at PALS. These shock waves are characterized by a developed radiative precursor and their dynamics is analyzed over long time scales (~50 ns), approaching a quasi-stationary limit. We present the first preliminary results on the rear side XUV spectroscopy. These studies are relevant to the understanding of the spectroscopic signatures of accretion shocks in Classical T Tauri Stars.Comment: 21 pages, 1 table, 7 figure

Structure of a laser-driven radiative shock

“…The aim of the experiments is to analyse the structure of a shock wave at low pressure (fraction of a bar) in xenon, in a regime of velocities of about 50 km s À1 , where the shock is preceded by a radiative precursor due to the intense radiative flux emerging from the post-shock [15,16,19]. Due to the high electron density in the post-shock region (about 10 21 cm À3 ), imaging of such high density plasmas requires a short wavelength and a short pulse probing back-lighting.…”

“…The target is closed by a gilt CH membrane (10 mm polystyrene and 0.5 mm gold) from the top on which laser beam is incident, where the polystyrene plays the role of the ablator, and the gold membrane aims at blocking hard X rays generated by the laser matter interaction to preheat the gas in the cell (see Refs. [16,19,18] for more details). The filling through the aluminium structure is here performed in situ, allowing to control precisely the pressure just before the shot.…”

Simulation of radiative shock waves in Xe of last PALS experiments

“…2 that tries to reproduce the geometry and materials of the original target used in PALS experiments [33,34]. The target forms a channel of 7 mm long with a squared section of 0.4 Â 0.4 mm 2 filled with Xe at 0.3 bar.…”

Design and fabrication of gas cell targets for laboratory astrophysics experiments on the Orion high-power laser facility

“…This is a further development of previous designs to enable the study of the more complex phenomena and instabilities that can arise in such a system [4] . Since 2000 there have been a number of designs for gas targets used in this field that have either had the features of tubes down which the plasma flow propagates or cells with windows [5][6][7] . The target design was optimized to allow for the shocks to propagate without interacting with the cell walls and for optical and X-ray diagnostics to be able to image the shocks as close as possible to their point of origin.…”