Charge Transfer in Constricted Form of Surface Barrier Discharge at Atmospheric Pressure

Houpt, Alec; Leonov, Sergey B.

doi:10.2514/1.t4970

Cited by 16 publications

(19 citation statements)

References 23 publications

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“…The electron number density, measured by Stark broadening of N + , reached ne = 9×10 18 cm -3 , representing an ionization of 36%. Such high electron number densities and temperatures were also measured by other teams in pin-to-pin configurations [10][11][12][13][14] and nanosecond Dielectric Barrier Discharges [15,16].…”

Section: Introductionsupporting

confidence: 63%

Ionization Mechanism in a Thermal Spark Discharge

Minesi

Mariotto

Stancu

et al. 2021

AIAA Scitech 2021 Forum

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The formation of thermal sparks generated by nanosecond pulses is studied experimentally and numerically. The increase of the electron number density, up to 10 19 cm -3 , is measured with sub-nanosecond resolution using Stark broadening of N + , Stark broadening of Hα, continuum emission of the electron, and the intensity of N + lines. Our experimental results are then compared to 0-D kinetic simulations including the electron-impact ionization of excited electronic states of N and O. The electron temperature, in equilibrium with the gas temperature, reaches 42,000K, which agrees with our experimental findings and the literature on the thermal spark.

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Section: Introductionsupporting

confidence: 63%

Ionization Mechanism in a Thermal Spark Discharge

Minesi

Mariotto

Stancu

et al. 2021

AIAA Scitech 2021 Forum

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“…A broadband radiation in a visible range of spectra with no traces of material of the electrode but with clearly detected lines of atomic nitrogen ions was recorded in discharge at P = 1 atm air in 3 cm gap under the voltage pulse 90 kV in amplitude [22]. Similar spectra, with atomic nitrogen ions lines dominated over the cw emission, were observed in [25] in the constricted SDBD powered by a burst of unipolar pulses 400 µs in duration and 20 kV in amplitude. It should be noted that the most of presented spectrum are socalled review spectrum not calibrated for the spectral sensitivity of the system, and the decay in the UV-region can be caused by the transmission of optics.…”

Section: Optical Emissionmentioning

confidence: 95%

Filamentary nanosecond surface dielectric barrier discharge. Experimental comparison of the streamer-to-filament transition for positive and negative polarities

Ding¹,

Khomenko²,

Shcherbanev³

et al. 2019

Plasma Sources Sci. Technol.

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Streamer-to-filament transition is a general feature of high pressure high voltage nanosecond surface dielectric barrier discharges (nSDBDs) for mixtures containing molecular gases. The transition is observed at high pressures and voltages in a single-shot experiment a few nanoseconds after the start of the discharge. A set of experimental results comparing streamer-to-filament transition and properties of plasma in the filaments for the identical high voltage pulses of negative and positive polarity is presented. The transition curves in voltage-pressure coordinates are obtained for N 2 :O 2 mixtures with different content of molecular oxygen, from 0 to 20%, at the pressure range 1-12 bar. Continuous optical spectra are compared for both polarities in 6 bar synthetic air. Electron density is calculated from Stark broadening of H α line at λ = 656.5 nm in the discharge and in early afterglow, 40 nanoseconds after the end of the high voltage pulse. Hydrodynamic perturbations are measured using schlieren imaging in 1-6 bar air for streamer and filamentary mode for both polarities. The review of common and distinctive features of the filamentary single-shot nSDBD for two polarities of the applied pulse is provided.

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“…The authors of Ref. [17] showed that the "contraction" of the discharge channel is associated with the appearance of a continuum spectrum and lines of N + , N, O, and Hα.…”

Section: Introductionmentioning

confidence: 99%

Fully ionized nanosecond discharges in air: the thermal spark

Minesi

Stepanyan

Mariotto

et al. 2020

Plasma Sources Sci. Technol.

106

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The formation and decay of the thermal spark generated by a single nanosecond highvoltage pulse between pin electrodes are characterized in this study. The influence of air pressure in the range 50 -1000 mbar is investigated at 300 K. By performing short-gate imaging and Optical Emission Spectroscopy (OES), we find that the thermal sparks exhibit an intense emission from excited electronic states of N + , in contrast with non-thermal sparks for which the emission is dominated by electronic transitions of N2. Spark thermalization consists of the following steps: (i) partial ionization of the plasma channel accompanied by N2 emission, (ii) creation of a fully ionized filament at the cathode characterized by N + emission, (iii) formation of a fully ionized filament at the anode, (iv) propagation of these filaments toward the middle of the interelectrode gap, and (v) merging of the filaments. The formation of the filaments, steps (ii) and (iii), occurs at subnanosecond timescales. The propagation speed of the filaments is on the order of 10 4 m/s during step (iv). For the 1-bar condition, the electron number densities are measured from the Stark broadening of N + and Hα lines, with spatial and temporal resolution. The electron temperature is also determined, from the relative emission intensity of N + excited states, attaining a peak value of 48,000 K. In the post-discharge, the electron number density decays from 4×10 19 to 2×10 18 cm -3 in 100 ns. We show that this decay curve can be interpreted as the isentropic expansion of a plasma in chemical equilibrium. Comparisons with previous experiments from the literature support this conclusion. Expressions for the Van der Waals and resonant broadenings of H, Hβ, and several lines of O, O + , N and, N + are derived in the appendix.

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Charge Transfer in Constricted Form of Surface Barrier Discharge at Atmospheric Pressure

Cited by 16 publications

References 23 publications

Ionization Mechanism in a Thermal Spark Discharge

Ionization Mechanism in a Thermal Spark Discharge

Filamentary nanosecond surface dielectric barrier discharge. Experimental comparison of the streamer-to-filament transition for positive and negative polarities

Fully ionized nanosecond discharges in air: the thermal spark

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