Enhanced oxygen dissociation in a propagating constricted discharge formed in a self-pulsing atmospheric pressure microplasma jet

Schröder, Daniel; Burhenn, Sebastian; Kirchheim, Dennis; Gathen, Volker Schulz-von der

doi:10.1088/0022-3727/46/46/464003

Cited by 18 publications

(16 citation statements)

References 31 publications

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“…The electron and ion density profiles show two symmetric peaks near the sheath boundary in the case of the 500 lm gap (upper panel), which is similar to experimental observations 33 in a SEE sustaining MD. On the other hand, in the case of the 100 lm gap (lower panel) the density profiles show only a single peak in the center.…”

Section: Discharge Behavior In a Wide Parameter Range A Effect supporting

confidence: 83%

“…5(b)-5(e) show that the electron temperature in the sheaths is much higher than the bulk electron temperature and can show several peaks, which indicates the prevalence of the c mode, in agreement with experiments. 33 In the plasma bulk, the electron temperature is lower than 0.1 eV, for all discharge gaps investigated, but it increases with increasing gap size, due to the transition from a pure c mode to a hybrid mode.…”

Section: B Effect Of Gap Sizementioning

confidence: 83%

“…First, it is important to realize that, despite the high collision frequency at atmospheric pressure, the ions and electrons do not necessarily exhibit a local behavior in a MD. When the discharge is in a so-called hybrid mode 33 (i.e., sustained by SEE), a "local discharge" means that the SEE electrons cannot reach the bulk region and most of them will lose their energy in the sheath. A "nonlocal discharge," on the other hand, means that the SEE electrons can reach or pass through the bulk region and induce ionization in the bulk plasma.…”

Section: Discharge Behavior In a Wide Parameter Range A Effect mentioning

confidence: 99%

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Computational study of plasma sustainability in radio frequency micro-discharges

Jiang

Zhang

et al. 2014

Journal of Applied Physics

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We apply an implicit particle-in-cell Monte-Carlo (PIC-MC) method to study a radio-frequency argon microdischarge at steady state in the glow discharge limit, in which the microdischarge is sustained by secondary electron emission from the electrodes. The plasma density, electron energy distribution function (EEDF), and electron temperature are calculated in a wide range of operating conditions, including driving voltage, microdischarge gap, and pressure. Also, the effect of gap size scaling (in the range of 50-1000 lm) on the plasma sustaining voltage and peak electron density at atmospheric pressure is examined, which has not been explored before. In our simulations, three different EEDFs, i.e., a so-called three temperature hybrid mode, a two temperature a mode, and a two temperature c mode distribution, are identified at different gaps and voltages. The maximum sustaining voltage to avoid a transition from the glow mode to an arc is predicted, as well as the minimum sustaining voltage for a steady glow discharge. Our calculations elucidate that secondary electrons play an essential role in sustaining the discharge, and as a result the relationship between breakdown voltage and gap spacing is far away from the Paschen law at atmospheric pressure. V

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Section: Discharge Behavior In a Wide Parameter Range A Effect supporting

confidence: 83%

Section: B Effect Of Gap Sizementioning

confidence: 83%

Section: Discharge Behavior In a Wide Parameter Range A Effect mentioning

confidence: 99%

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Computational study of plasma sustainability in radio frequency micro-discharges

Jiang

Zhang

et al. 2014

Journal of Applied Physics

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“…The established procedure consists of a reference measurement in a defined xenon atmosphere, created in the closed vessel [32,34]. It is described in detail for the particular experimental setup in a recent publication of the authors [33].…”

Section: Detection Of O Radical: Talif Spectroscopymentioning

confidence: 99%

Absolute OH and O radical densities in effluent of a He/H₂O micro-scaled atmospheric pressure plasma jet

Benedikt

Schröder

Schneider

et al. 2016

Plasma Sources Sci. Technol.

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The effluent of a micro-scaled atmospheric pressure plasma jet (μ-APPJ) operated in helium with admixtures of water vapor (10 4 ppm) has been analyzed by means of cavity ring-down laser absorption spectroscopy and molecular beam mass spectrometry to measure hydroxyl (OH) radical densities, and by two-photon absorption laser-induced fluorescence spectroscopy to measure atomic oxygen (O) densities. Additionally, the performance of the bubbler as a source of water vapor in the helium feed gas has been carefully characterized and calibrated. The largest OH and O densities in the effluent of × − 2 10 cm 14 3 and × − 3.2 10 cm 13 3 , respectively, have been measured at around 6000 ppm. The highest selectivity is reached around 1500 ppm, where the OH density is at ∼63% of its maximum value and is 14 times larger than the O density. The measured density profiles and distance variations are compared to the results of a 2D axially symmetric fluid model of species transport and reaction kinetics in the plasma effluent. It is shown that the main loss of OH radicals in the effluent is their mutual reaction. In the case of O, reactions with other species than OH also have to be considered to explain the density decay in the effluent. The results presented here provide additional information for understanding the plasma-chemical processes in non-equilibrium atmospheric pressure plasmas. They also open the way to applying μ-APPJ with He/H 2 O as a selective source of OH radicals.

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“…Moreover, the self-pulsing discharge mode could be the source of many reactive species generated during the rising of peak current pulses. 1,[29][30][31][32] Therefore, to fit to the purpose of each plasma application, atmospheric non-thermal dc plasma jet could be controlled by the aforementioned method.…”

Section: Discussionmentioning

confidence: 99%

DC non-thermal atmospheric-pressure plasma jet generated using a syringe needle electrode

Matra¹

2016

Jpn. J. Appl. Phys.

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Non-thermal plasma jet was generated by applying a dc source voltage between the syringe needle anode with flowing Argon gas and a planar or a hollow copper cathode in an atmospheric-pressure environment. The two operating discharge modes, which were self-pulsing and a continuous discharge mode, these were mainly controlled by the limitations of the current flowing in the discharge circuit. A ballast resistor was an important factor in affecting the limitations of the operating discharge mode. The gas breakdown was initially generated in the self-pulsing discharge mode at the source voltage of 1.2 kV. This was slightly higher than the breakdown voltage at the experimental condition of 1 lpm of Argon and a 1 mm electrode gap distance. The peak self-pulsing discharge currents were up to 15–20 A with a self-pulsing frequency in the range of 10–20 kHz. The continuous discharge mode could be observed at the higher source voltage with the continuous discharge current within the range of a few milliamperes.

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Enhanced oxygen dissociation in a propagating constricted discharge formed in a self-pulsing atmospheric pressure microplasma jet

Cited by 18 publications

References 31 publications

Computational study of plasma sustainability in radio frequency micro-discharges

Computational study of plasma sustainability in radio frequency micro-discharges

Absolute OH and O radical densities in effluent of a He/H₂O micro-scaled atmospheric pressure plasma jet

DC non-thermal atmospheric-pressure plasma jet generated using a syringe needle electrode

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Enhanced oxygen dissociation in a propagating constricted discharge formed in a self-pulsing atmospheric pressure microplasma jet

Cited by 18 publications

References 31 publications

Computational study of plasma sustainability in radio frequency micro-discharges

Computational study of plasma sustainability in radio frequency micro-discharges

Absolute OH and O radical densities in effluent of a He/H2O micro-scaled atmospheric pressure plasma jet

DC non-thermal atmospheric-pressure plasma jet generated using a syringe needle electrode

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Product

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Absolute OH and O radical densities in effluent of a He/H₂O micro-scaled atmospheric pressure plasma jet