Argon chemical kinetics model with uncertainty quantification for simulations of a capacitively coupled plasma discharge*

In a non-equilibrium plasma discharge model, an accurate finite-rate chemistry mechanism is required to capture correctly all the reactive collisional phenomena that occur in the discharge. A pure argon chemistry mechanism was developed to be used in high pressure (>1 Torr), non-equilibrium plasma discharges, and a preliminary validation assessment under uncertainty was performed against experimental data. The validation target is the number density of the higher excited states belonging to the 4p manifold. The kinetic model includes 6 species (E, Ar⁺, Ar_m, Ar_r, Ar_4p and Ar) and 34 reactions. Rate coefficients for electron-impact processes were obtained by integrating the cross-sections through BOLSIG+, and their uncertainties were quantified according to the scatter of the data in the literature, whereas for heavy-heavy reactions, the rate coefficients were obtained directly from the literature. Current comparison with experimental data shows a good agreement, especially in the 1 Torr regime. Simulations at higher pressures are currently being done.

Furthermore, the use of statistical tools, such as sensitivity analysis and mutual information, will be implemented to assess the quality of validation efforts, as well as to determine the most important parameters that can be tuned in the model to better predict the experimental observations.