THEORETICAL INVESTIGATION OF THE APPARENT SPECTRAL RADIANCE FROM THE METAL WINDOW INTERFACE IN SHOCK TEMPERATURE EXPERIMENTS/

When a shock wave passes through an ideal metal/window interface, the interface temperature is time independent; accordingly, the apparent s pectral radiance at the interface is also regarded as time independent . However, each material has a definite transparency, so that the appa rent spectral radiance at the interface must be the total radiance of a thin layer rather than the surface, In this article, the relationshi p among the optical absorption coefficient of a metal and its pressure and temperature is studied based on classical electromagnetics. It is obtained that the absorption coefficient decreases and the optical de pth increases as shock pressure increases, By using the radiative tran sport equation, the apparent spectral radiance at the ideal iron/sapph ire interface following shock compression is calculated, which shows t hat the apparent spectral radiance is time dependent, although the int erface temperature is time independent. As an example, the apparent sp ectral radiance history at the iron/sapphire interface under shock pre ssure of about 230 GPa is presented. (C) 1998 American Institute of Ph ysics.