EXPERIMENTAL AND SIMULATED PROFILES OF THE AL-XIII LY-ALPHA RESONANCELINE FROM A CYLINDRICALLY EXPANDING PLASMA

Spectral profiles of optically thick line radiation emitted by an expa nding cylindrical laser-produced plasma have been recorded in high res olution using a vertical dispersion variant of the double-crystal spec trometer. By uniformly irradiating a narrow wire with a 1 ns pulse a q uasi-steady plasma expansion is generated with a velocity gradient in excess of 10(9) s(-1). Such velocity fields strongly influence the tra nsfer of radiation through a plasma, resulting in a complex distortion of the lineshapes of optically thick lines. We have computed theoreti cal profiles of the Al XIII Ly-alpha resonance line. Simulation of the laser-plasma interaction is performed using the 1D Lagrangian hydroco de MED103 which incorporates a non-LTE time-dependent excitation and i onisation package based on the average-atom model. Line emission profi les are calculated by the method of multi-frequency line transfer in t he co-moving frame. We investigate the sensitivity of the lineshape on plasma parameters such as the velocity profile, comparing our theoret ical predictions with experiment. (C) 1997 Published by Elsevier Scien ce Ltd. All rights reserved.