X-ray line reabsorption in a rapidly expanding plasma

We present high-resolution spectroscopic measurements of the optically thic k hydrogen-like Al Ly-alpha a line shape from a cylindrically expanding pla sma. The cylindrical expansion is produced by symmetrically irradiating a 1 20 mu m diameter coated wire target with six beams of the VULCAN Nd:glass l aser at an irradiance of 2 x 10(14) W cm(-2). Small shifts in the line posi tion and changes in the line shape can be attributed to radiation emitted f rom different regions of the plasma and passing through different gradients in plasma density, temperature, and velocity. The experimental profiles ar e compared to a time-dependent hydrodynamics code incorporating a Sobolev e scape probability treatment of the radiative transport. (C) 2000 Elsevier S cience Ltd. All rights reserved.