An alternative quantitative analysis of non-equilibrium transport coefficients in argon plasmas

To describe plasmas in non-local thermal equilibrium (non-LTE) four parameters need to be used, which are usually besides the pressure and the electron temperature, the electron density and the atom temperature. In the approach presented here it is argued that the use of four other variables is preferable. These four parameters are the total pressure, the ratio of the electron density and the squares root of the total pressure, and two specific non-equilibrium parameters. The non-equilibrium parameters are chosen such that they describe deviations from ionization-recombination equilibrium, and deviations from temperature equilibrium. It appears that the influence of deviations from complete LTE on the transport coefficients is often small when the parameters are scaled with the electron density and the pressure. In this way, the non-LTE transport properties can be estimated by using complete LTE transport coefficients without losing much accuracy.