Ultra-fast development of Ar 2p 1−10 relative densities in nanosecond-pulsed barrier discharge in argon

Abstract

A time-correlated single photon counting based optical emission spectroscopy technique is applied for an investigation of the nanosecond-pulsed barrier discharge in atmospheric pressure argon gas. We record the development of the light intensities originating from all ten Ar 2p1-10 (Paschen notation) radiative states with high spatio-temporal resolution. We identify different stages of the discharge development: an early rapid electron avalanching, streamer propagation phase, generation of discharge channel and surface streamer propagation over the dielectric surface. The quantified relative 2p1-10 densities for identified discharge phases enable a well-resolved insight into the ultra-fast discharge kinetics and open a possibility for the development of future detailed diagnostics of the rapidly ionized argon plasmas. Moreover, the electrical characterization of the discharge is made using the simplest equivalent circuit and it reveals new findings for the application of such an approach for similar discharges.

Remote streamer initiation on dielectric surface

“…As the excitation energy thresholds for 2p states differ relatively only slightly, their use for the intensity ratio method is expected to be challenging. Nevertheless, the experimental results presented in [22] report clearly that 2p state intensity ratios are sensitive to the spatiotemporal dynamics of the nanosecond pulsed discharge, if recorded with high sensitivity and high temporal resolution.…”

“…Figure 1 shows the discharge arrangement together with typical voltage and current waveforms in the repetitive regime. The electrode arrangement considered in the simulations was the same as in previous experimental and theoretical investigations [22,27,38]. An asymmetric volume barrier discharge with one electrode covered by the alumina dielectric (96% purity Al 2 O 3 ) is studied.…”

“…The gas gap is 1.5 mm, the dielectric thickness is 0.5 mm (in [38], wrong value of the dielectric thickness of 1 mm) is given for the same setup, the dielectric's permittivity is ε r = 9, and the radius of the electrode surfaces is 2 mm. Later in this article, the developed theoretical approach is applied to the experimental data obtained in [22]. Those experiments were done under the following conditions: The electrodes are in the sealed glass chamber evacuated to high vacuum (10 −5 mbar), heated to 700 K for several hours (baked out to reduce impurities) and then filled with argon gas of high purity of 99.9999% to atmospheric pressure.…”

“…Those experiments were done under the following conditions: The electrodes are in the sealed glass chamber evacuated to high vacuum (10 −5 mbar), heated to 700 K for several hours (baked out to reduce impurities) and then filled with argon gas of high purity of 99.9999% to atmospheric pressure. In the previous work [22], the emission in the pulsed barrier discharge was investigated by photomultipliers PMC-100-20 and PMC-100-4 and processed by timecorrelated single photon counting module SPC-150 from Becker and Hickl GmbH. The voltage and current measurements were conducted by P6015A voltage probe (Tektronix) and current transformer CT-2 (Tektronix), respectively.…”

“…Up to now, we have developed a solid theoretical foundation by creating an enhanced reaction kinetics model (see [1]) used for spatially one-dimensional (1D) modelling, by developing a spatially two-dimensional (2D) fluid model for casespecific computer simulations (see [27,36,37]) and by performing first 2p spectra measurements with sufficiently high temporal and spatial resolution to establish the link to the experiment (see [22]). Here, a dielectric barrier discharge in an asymmetrical arrangement (only one electrode is covered by a dielectrics) and operated by nanosecond pulsed voltage waveform at various frequencies is studied using numerical simulations.…”