Stark-Broadening Measurements of 3d->nf Transitions in Lithiumlike and Heliumlike Ions

We report here on high-resolution spectral measurements of Stark-broadened 3d-5f lines from lithiumlike ions and 3d-4f lines from heliumlike ions. The spectra were emitted from high-density laser-produced plasmas. Plasmas were produced by irradiating thin- and thick-foil targets made of magnesium, aluminum, phosphorus, and chlorine with the OMEGA laser in a line-focus geometry. Line profiles were compared to a Stark-broadening calculation that uses the static-ion approximation and an impact approximation for the electrons. The dependence of Stark broadening on atomic number is discussed. For the aluminum plasmas ∼10% narrowing was observed in the width of the 3d-5f line as the length of the plasma was increased from 3 to 6 mm.