The electron energy distribution function (EEDF) in an afterglow of a pulsed direct current discharge has been measured in an Ar:N-2 mixture by means of a time-resolved Langmuir probe technique. The vibrational temperature, T-nu, of N-2 molecules has also been experimentally estimated. The results show that a correlation between an effective electron temperature, T-e, and T-nu strongly varies with experimental conditions. In particular the conditions exist under which the rapid decrease from high to low T-e values is observed at some moment after the discharge pulse, while the vibrational temperature remains almost constant.
The theoretical study of the EEDF in Ar:N-2 afterglow plasma has also been made by the numerical solution of an appropriate Boltzmann equation by taking into account electron-electron collisions as well as superelastic vibrational and superelastic electronic collisions. Calculations show that for a given T-nu the value of T-e depends on the electron concentration, n(e). Moreover, the ranges of n(e) and T-nu exist, where two different solutions of Boltzmann equations can be obtained.
Finally, the comparison of the theoretical and experimental results is performed and an explanation of the experimentally observed phenomenon is given.