Collisional-radiative ionization and recombination in an inductively coupled argon plasma

Abstract

The extensive collisional-radiative model is applied to the actual argon inductively coupled plasma (ICP) in order to quantify the extent of the ionization-recombination non-equilibrium in selected spatial positions, and to determine the corresponding rates of the electron production or disappearance due to ionization and recombination, respectively. Computations are carried out for various sets of input parameters, such as the electron temperature T e, the atom temperature T a, the electron number density n e, the ground-state atom population n 1, the plasma column radius R and the escape factors Λ mn and Λ m . The numerical results, illustrating the non-homogeneous structure of the ICP, show that the extent of the local ionization-recombination non-equilibrium, and the rate of the electron production or disappearance due to the collisional and radiative processes in the “pure” argon plasma, are strongly dependent on the electron temperature and are significantly affected by resonance radiation trapping, but are almost independent of the atom-atom inelastic collisions. It is also shown that recombination via excited argon states is an important recombination channel in the axial region of the normal analytical zone of the ICP.