Time-dependent kinetics of electrons and 3p⁵4s levels of argon in high frequency plasmas

We present a theoretical investigation of the time-dependence of the electron energy distribution function and the populations in the 3p 5 4s levels of argon under the action of a harmonic electric field, assuming the electron density is constant with time. The analysis is based on the solutions to the time-dependent Boltzmann equation and the system of rate balance equations for the populations in the 3p 5 4s levels. It is shown that the results of this temporal analysis may be explained in terms of the characteristic relaxation frequencies for electron-neutral momentum transfer, electron energy transfer, and for the relaxation of each 3p 5 4s level. The assumption of time-invariance of electron density is discussed and analysed. The present theory covers a very broad range of field frequencies, from the microwave case down to frequencies of approximately=100 KHz.