266 / 2023-04-23 19:43:17

Experimental Study of Radiative Shock on the 100kJ Laser Facility

radiative shock,high energy density physics,heat wave,absorption spectroscopy

辐射和流体力学 > 高能量密度科学与温稠密物质-I

The temperature of compressed material at the shock wave front with a high-speed will be so high to radiate to form a heat wave ahead of the shock wave, which may affect the structure of the shock wave itself. This process is called radiative shock which is relevant to many astrophysics phenomena and is a research frontier in high energy density physics study. Experiments was performed on the 100kJ laser facility to study the radiative effect of such a shock wave. 24 laser beams from one of the hemisphere of the laser facility with 1.2ns pulse width and 1TW peak power were injected into a gold halfraum to generate an intensive radiation source with peak equivalent radiation temperature about 280eV. This radiation was used to ablate a Al foil and drive a shock wave which then propagate into a Cl-doped low density CH foam. A shock wave speed above 100km/s was achieved, which then generated a radiative precursor. Back-lighting recorded with x-ray streak camera was used to diagnose the shock wave fronts. Absorption spectroscopy was used to measure the radiative precursor with spatial resolution. The density and temperature distribution were derived from the intensity distribution and characteristic absorption lines. By comparison with numerical simulations, the experimental results showed a clear proof of the radiative precursor which validates the method for radiative shock diagnostics. This study is very important for the understanding of the radiative shock process and fro the validation of the radiation hydrodynamics codes.