Two-dimensional axisymmetric models of laser induced plasmas relevant to laser induced breakdown spectroscopy

• A gas dynamic model of laser induced plasma with axial symmetry is developed.
• The effects of the plasma equation of state, radiation transfer, transport phenomena, and the ablation surface on the plasma evolution and the plasma spectra are systematically studied.
• Numerous numerical simulations visualize the physical portrait of the plasma at different stages of its evolution.
• The model provides a numerical tool to assess various settings for LIBS plasma experiments and to interpret experimental data.

A dynamical model of a laser induced plasma with axial symmetry is developed to systematically study the effects of the plasma equation of state, radiation transfer, various transport phenomena (viscosity, thermal conductivity, diffusion), and the ablation surface on the observable quantities such as spectra emitted by LIBS plasmas containing multiple species. Theoretical and numerical foundations of the model are described in detail. It is shown that the plasma spectra simulated with the equation of state based on the energy balance that includes the kinetic (thermal) energy, ionization energy, and energy of electronic excitations in atoms and ions differ significantly from the spectra obtained for plasmas modeled in the ideal gas approximation (where only the kinetic energy is included into the energy balance). Various transport phenomena, such as viscosity, diffusion, and thermal conductivity, are shown to have a little effect on the spectra. Radiation losses are proved to have noticeable effects. The effects of various interactions (adhesion, heat exchange, mass inflows) of the evolving plasma with the ablation surface are also illustrated by numerical simulations for typical LIBS plasmas. The model provides a numerical tool to assess various settings for LIBS plasma experiments as well as to interpret experimental data.