Stark broadening of Mg I and Mg II spectral lines and Debye shielding effect in laser induced plasma

• Stark broadening parameters for three Mg I and one Mg II line.
• Comparison of Stark parameters with other experimental and theoretical results.
• Recommendation of Mg II 448.1 nm line for plasma diagnostics.
• Influence of Debye shielding effect to line widths of Mg I 383.53 nm multiplet.
• Application of laser induced plasma for Stark broadening parameters measurement.

We report Stark broadening parameters for three Mg I lines and one Mg II line in the electron number density range (0.67–1.09) · 1017 cm− 3 and electron temperature interval (6200–6500) K. The electron density is determined from the half width of hydrogen impurity line, the Hα, while the electron temperature is measured from relative intensities of Mg I or Al II lines using Boltzmann plot technique. The plasma source was induced by Nd:YAG laser radiation at 1.06 μm having pulse width 15 ns and pulse energy 50 mJ. Laser induced plasma is generated in front of a solid state surface. High speed photography is used to determine time of plasma decay with good homogeneity and then applied line self-absorption test and Abel inversion procedure. The details of data acquisition and data processing are described and illustrated with typical examples. The experimental results are compared with two sets of semiclassical calculations and the results of this comparison for Mg I lines are not unambiguous while for Mg II 448.1 nm line, the results of Dimitrijević and Sahal-Bréchot calculations agree well with our and other experimental results in the temperature range (5000–12,000) K and these theoretical results are recommended for plasma diagnostic purposes. The study of line shapes within Mg I 383.53 nm multiplet shows that the use of Debye shielding correction improves the agreement between theoretical and experimental Stark broadening parameters.