Pulsed RF discharges, glow and filamentary mode at atmospheric pressure in argon

Balcon, N.; Aanesland, Ane; Boswell, Roderick

doi:10.1088/0963-0252/16/2/002

Cited by 176 publications

(115 citation statements)

References 21 publications

Supporting

Mentioning

100

Contrasting

Unclassified

Order By: Relevance

“…9 Dielectric barrier discharges working with either sinusoidal signals around 10-100 kHz, where the dielectric prevents the formation of the high temperature arcs, are the most common atmospheric pressure system currently in use. 10 In this particular plasma source, the diameter of quartz capillary ͑and consequently, interelectrode gap͒ was reduced in order to obtain stable plasma with long afterglow zone. Commonly used technique for atmospheric pressure discharges investigations is optical emission spectroscopy ͑OES͒.…”

Section: Introductionmentioning

confidence: 99%

Atmospheric pressure plasma jet in Ar and Ar/H2O mixtures: Optical emission spectroscopy and temperature measurements

2010

View full text Add to dashboard Cite

An atmospheric pressure plasma jet generated in Ar/water vapor mixtures has been investigated and the effect of water content on plasma properties has been studied. Plasma generated in Ar/water ͑0.05%͒ mixture shows higher intensity of OH radicals in emission spectra than pure argon alone. Plasma density has been estimated from current measurement and is in order of 1.5ϫ 10 13 cm −3 . Electron temperature has been estimated as 0.97 eV in pure Ar and it decreases with an increase in water content in plasma. The gas temperature has been determined by fitting of the experimental spectra and using the Boltzmann plot method. The gas temperature increases with the addition of water to feed gas from 620 K in pure Ar up to 1130 K for 0.76% H 2 O.

show abstract

Section: Introductionmentioning

confidence: 99%

Atmospheric pressure plasma jet in Ar and Ar/H2O mixtures: Optical emission spectroscopy and temperature measurements

2010

View full text Add to dashboard Cite

show abstract

“…Self-organized structures appear in numerous gases and in a wide parameter range. They become investigated in low frequency devices as well as in radio frequency discharges [1,4]. Besides the pattern formation itself, their temporal dynamic has been investigated in the past [6,10,11,13].…”

Section: Introductionmentioning

confidence: 99%

Interaction of current filaments in dielectric barrier discharges with relation to surface charge distributions

Stollenwerk¹

2009

New J. Phys.

View full text Add to dashboard Cite

Abstract. In a planar, laterally extended dielectric barrier discharge (DBD) system operated in glow mode, a filamentary discharge is observed. The filaments tend to move laterally and hence tend to cause collisions. Thereby, usually one collision partner becomes destroyed. In this paper, the collision process and especially the preceding time period is investigated. Beside the luminescence density of the filaments, the surface charge density accumulated between the single breakdowns of the DBD is observed via an optical measurement technique based on the linear electro-optical effect (pockels effect). A ring-like substructure of the surface charge distribution of a single filament is found, which correlates to the filament interaction behaviour. Furthermore, a preferred filament distance is found, suggesting the formation of a filamentary quasi-molecule.

show abstract

“…The spectral line emitted from plasma is subject to various broadening mechanisms except instrumental broadening, such as natural, Doppler, resonance, van der Waals, and Stark broadening. The natural (6.2 × 10 −5 nm [21]), resonance, and van der Waals broadening are generally negligible in low-pressure plasma. Doppler broadening � Doppler 1/2 follows Gaussian profile, the same as instrumental broadening.…”

Section: Oes Systemmentioning

confidence: 99%

Determination of the number densities of CH(X2Π) and CH(A2Δ) radicals in a DC cascaded arc discharge plasma

Wang

et al. 2015

Appl. Phys. B

View full text Add to dashboard Cite

radical-based chemistry generally dominates in any eventual material processing in the plasma jet.The CH radical is a common intermediate in reactive chemical systems with hydrocarbons [6]. Monitoring CH provides an insight into the reaction mechanism. CH radicals and C atoms contribute to the experimentally observed high and nonuniform diamond growth rates in the highpower Bristol reactor [7]. The level of CH concentration agreement between the model prediction and the experimental measurement can be used to test model predictions of hydrocarbon chemistry [8]. CH also is a probe species to determine the chemical erosion of carbon-based materials in divertor [9].Optical emission spectroscopy (OES) is arguably the simplest and most straightforward means to investigate the CH behavior in the plasma. The OES signal is proportional to the population density of the upper state, and the interpretation of OES data is complicated which needs a proper understanding of the various species excitation and de-excitation processes, especially when the plasma does not close to local thermodynamic equilibrium (LTE). Generally, the ground electronic state radicals and molecules are inevitably present in higher concentrations than their electronically excited counterparts and dominate the thin film deposition [10]. Thus, it is necessary to measure the majority species populating ground and low-lying electronic states.To diagnose the ground state, absorption spectroscopy is a preferred approach. Cavity ring-down spectroscopy (CRDS) [11] provides the diagnostic of choice to obtain the absolute number densities without the need for additional calibration standards. The technique measures the time decay of a laser pulse trapped in a high-finesse optical cavity. Effectively, it is a multi-pass technique in which the optical path length may be tens of kilometers. Thus, it is a versatile, highly sensitive, linear absorption technique.Abstract A combination of optical emission spectroscopy (OES) and cavity ring-down spectroscopy (CRDS) has enabled to determinate the number densities of CH(A 2 Δ) and CH(X 2 Π) radicals simultaneously in a cascaded arc plasma reactor operating with a CH 4 /Ar mixture. It is found that the number density of CH(A 2 Δ) radical increases with discharge current at first and then decreases. However, the number density of CH(X 2 Π) radical decreases with discharge current when the rate of CH 4 flow to total flow is lower than 1 %, while it increases slightly with discharge current when the rate is 1.5 %. The results reveal that CH radicals are deviation from excitation equilibrium. Although OES is the simplest and most straightforward means to investigate the CH radical behavior, it is not enough to provide the information of the CH(X 2 Π) number density, and additional methods, such as CRDS, are needed in the cascaded arc plasma jet.

show abstract

Pulsed RF discharges, glow and filamentary mode at atmospheric pressure in argon

Cited by 176 publications

References 21 publications

Atmospheric pressure plasma jet in Ar and Ar/H2O mixtures: Optical emission spectroscopy and temperature measurements

Atmospheric pressure plasma jet in Ar and Ar/H2O mixtures: Optical emission spectroscopy and temperature measurements

Interaction of current filaments in dielectric barrier discharges with relation to surface charge distributions

Determination of the number densities of CH(X2Π) and CH(A2Δ) radicals in a DC cascaded arc discharge plasma

Contact Info

Product

Resources

About