Spatio-temporal dynamics of a microsecond pulsed Grimm-type glow discharge

Abstract

Spatio-temporal dynamics of a Grimm-type microsecond pulsed glow discharge (μPGD), that operates in abnormal glow regime in argon at 6 mbar, is presented. The occurrence of a high current peak during the ignition of the discharge was analyzed and the importance of taking into account the displacement current was pointed out. A development of the electron excitation temperature of argon atoms and argon ions was measured at several distances from the cathode. Spatio-temporal evolution of the intensity of selected spectral lines of atoms and ions of argon and copper were measured and analyzed during the three phases of the discharge development: pre-peak, steady-state and afterglow. The spectral line emissions have different behavior during the pre-peak and the afterglow of the discharge – the lines with low upper-level energies get the maximum intensity in the pre-peak period, while the lines with high upper-level energies get the maximal intensity in the afterglow period. The time of the appearance of the afterpeak maxima and the afterpeak decay time are shorter for the ions than for the atoms. The results are explained primarily in terms of three-body recombination processes and ion mobilities. Carefully arranged and conducted experiment with a large amount of experimental data, together with analysis of excitation and deexcitation processes, could be useful for more precise modeling of μPGD, as well as a note for selection of adequate spectral lines and discharge conditions for more accurate analytical measurements.