Diagnostics of a laser-induced dense plasma by hydrogen-like carbon spectra

The interpretation of a measured x-ray spectrum from a carbon plasma induced by subpicosecond laser pulses (Wilhein T et al 1998 J. Opt. Soc. Am. B 15 1235) is re-examined. We calculate a synthetic Lyman spectrum emitted from a plasma layer at a given temperature and density, using a microscopic approach to the lineshape in dense, non-ideal plasmas. Special attention is given to the Stark broadening of the Ly-γ line. Self-absorption is taken into account within a simple model considering one-dimensional radiation transport in a plasma layer. Comparing the synthetic spectrum with the experimental one, we infer a temperature of T = 106 K and an electron density of ne = 3x1021 cm-3. While the temperature is in agreement with Wilhein et al, the inferred density disagrees by one order of magnitude. (author)