Numerical modeling of the constriction of the dc positive column in rare gases

Petrov, G. M.; Ferreira, C. M.

doi:10.1103/physreve.59.3571

Cited by 73 publications

(63 citation statements)

References 19 publications

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“…Losses of charged particles at pressures higher than approximately 1 kPa occur mainly through dissociative recombination, a case of volume recombination. 8,47,55,56 This process, which is the most effective recombination mechanism at such high pressures, is known to increase with gas density. 55 Because N increases from the axis toward the wall, E/N decreases, and so does the ionization rate, while the charged particle losses increase.…”

Section: Summary Of the Modeling Of Contracted Dischargesmentioning

confidence: 98%

“…32,35,[41][42][43][44][45][46][47][48][49][50][51][52][53][54] This phenomenon was interpreted mainly on the basis of a radially nonuniform heating of the discharge gas, as will be discussed later.…”

Section: Summary Of the Modeling Of Contracted Dischargesmentioning

confidence: 99%

“…[47][48][49][50][51][52][53][54] The plasma filament orientation, position, and shape depend on: ͑iv͒ Electric field direction: orientation of the plasma filament The contracted discharge filament is oriented along the discharge tube axis when its sustaining electric field is directed along this same axis. ͑v͒…”

Section: Summary Of the Modeling Of Contracted Dischargesmentioning

confidence: 99%

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Radial contraction of microwave-sustained plasma columns at atmospheric pressure

Kabouzi

Calzada

Moisan

et al. 2002

Journal of Applied Physics

151

139

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Plasma columns sustained at high enough gas pressures undergo radial contraction as manifested by their glow not entirely filling the radial cross-section of the discharge tube. This phenomenon has been reported with direct current, radio frequency, and microwave discharges. However, its modeling is still incomplete, in particular for rf and microwave discharges, a situation attributed to a lack of experimental data. To fill this gap, we took advantage of the extreme flexibility in terms of field frequency, tube diameter and gas nature of surface-wave sustained discharges to achieve a parametric study of this phenomenon. Special attention was paid to filamentation, specific to rf and microwave discharges, which is the breaking of a single channel of plasma into two or more smaller filaments as a result of the skin effect. We used emission spectroscopy as the main diagnostic means. Electron density was obtained from Stark broadening of the Hβ line, while molecular-band spectra emitted by the OH radical and the N2+ molecule were employed to determine the discharge gas temperature, leading to its radial distribution upon performing Abel inversion. For a given tube radius, contraction is shown to increase with decreasing thermal conductivity of the discharge. As a result, He and N2 discharges are the least contracted, while contraction increases with increasing atomic mass of noble gases. Of all these discharges, the N2 discharge appears to be the closest to local thermodynamic equilibrium.

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Section: Summary Of the Modeling Of Contracted Dischargesmentioning

confidence: 98%

Section: Summary Of the Modeling Of Contracted Dischargesmentioning

confidence: 99%

Section: Summary Of the Modeling Of Contracted Dischargesmentioning

confidence: 99%

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Radial contraction of microwave-sustained plasma columns at atmospheric pressure

Kabouzi

Calzada

Moisan

et al. 2002

Journal of Applied Physics

151

139

View full text Add to dashboard Cite

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“…[39][40][41][42][43][44][45][46] In contrast to dc discharges where the contracted discharge always takes the form of a single straight filament, rf and microwave discharges can also yield two or more plasma filaments depending on dis- charge operating conditions. 26 The plasma-free region, resulting from the contraction effect, limits the abatement efficiency, as will be discussed in Sec.…”

Section: The Phenomenon Of Contraction In Microwave Discharges At mentioning

confidence: 99%

Abatement of perfluorinated compounds using microwave plasmas at atmospheric pressure

Kabouzi

Moisan

Rostaing

et al. 2003

Journal of Applied Physics

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Microwave plasmas sustained at atmospheric pressure, for instance by electromagnetic surface waves, can be efficiently used to abate greenhouse-effect gases such as perfluorinated compounds. As a working example, we study the destruction and removal efficiency (DRE) of SF6 at concentrations ranging from 0.1% to 2.4% of the total gas flow where N2, utilized as a purge gas, is the carrier gas. O2 is added to the mixture at a fixed ratio of 1.2–1.5 times the concentration of SF6 to ensure full oxidation of the SF6 fragments, providing thereby scrubbable by-products. Fourier-transform infrared spectroscopy has been utilized for identification of the by-products and quantification of the residual concentration of SF6. Optical emission spectroscopy was employed to determine the gas temperature of the nitrogen plasma. In terms of operating parameters, the DRE is found to increase with increasing microwave power and decrease with increasing gas flow rate and discharge tube radius. Increasing the microwave power, in the case of a surface-wave discharge, or decreasing the gas flow rate increases the residence time of the molecules to be processed, hence, the observed DRE increase. In contrast, increasing the tube radius or the gas-flow rate increases the degree of radial contraction of the discharge and, therefore, the plasma-free space close to the tube wall: this comparatively colder region favors the reformation of the fragmented SF6 molecules, and enlarging it lowers the destruction rate. DRE values higher than 95% have been achieved at a microwave power of 6 kW with 2.4% SF6 in N2 flow rates up to 30 standard l/min.

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“…T HE propagation of charged beams transported through neutral gas or plasma has been studied in detail in [1]- [33]. Often, the charged beam will propagate through the gas or plasma in a pinched mode [1], [22], [29], instead of breaking up as one would expect from like-charge coulombdriven particles.…”

Section: Introductionmentioning

confidence: 99%

Nonlinear Theory Modeling Electron Beam Constriction in a Pulsed Power Discharge

Andersen

Schill

2015

IEEE Trans. Plasma Sci.

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A simple nonlinear theory is developed to examine the process of electron channeling and constriction for an energetic electron beam passing through a cool thermalized plasma discharge. A number of different perturbations characterize and categorize the physical process of the three-fluid system. In this model, the electron species is separated into two different species of the same type but with very different initial particle states. A normalized set of curves parameterize the conditions most probable leading to electron channeling and pinch (beam constriction) in a pulsed power glow discharge. The theory suggests that energetic secondary electron emission at the cathode is responsible for glow discharge constriction in a pulsed power discharge.

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Numerical modeling of the constriction of the dc positive column in rare gases

Cited by 73 publications

References 19 publications

Radial contraction of microwave-sustained plasma columns at atmospheric pressure

Radial contraction of microwave-sustained plasma columns at atmospheric pressure

Abatement of perfluorinated compounds using microwave plasmas at atmospheric pressure

Nonlinear Theory Modeling Electron Beam Constriction in a Pulsed Power Discharge

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