Modelling of ionization composition in argon plasma with fast electrons

Discharge and laser produced plasmas often have nonequilibrium electron distribution with fast electrons that may have a profound effect on ionization balance. The influence of high energy electrons on ionization balance in the collisional-radiative equilibrium model for the optically thin plasma is considered. Nonmaxwellian electron distribution with various concentration and energy of fast electrons is used for calculations of impact rates on the basis of Hartree-Fock-Slater (HFS) quantum-statistical model in the average atom approximation. The calculation approach is based on the method of distorted waves with using numerical and semiclassical wave functions calculated in the self-consistent HFS potential. Results of modelling of the ionization equilibrium in argon plasma at temperatures $T\sim{}$ 5 – 1000 eV with fast electron energies from 1 to 10 keV and relative concentrations 0.1 – 10% are analyzed. It is shown that fast electrons increase the impact ionization rates and significantly change the equilibrium ionization stage.