The Townsend coefficient of ionization in dense gases and fluids

Atrazhev, V.M.; Iakubov, I. T.; Roldughin, V. I.

doi:10.1088/0022-3727/9/12/013

Cited by 27 publications

(27 citation statements)

References 14 publications

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“…V b = f (p × d, d) has been illustrated in several researches. [6][7][8][9][10][11][12].This voltage is higher for cylindrical geometry than for plane one. [13] The breakdown voltages of gases are follow up Paschen's law in parallel-plate geometries, but it is not directly applicable in non-planar geometries, because of the confusion about the distance between the electrodes and distortion of the electric field.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Electrical Breakdown for Low and High Pressure Hydrogen Gas in Coaxial Virtual Cathode Device

Shagar

Ebrahim

Al-Halim

et al. 2018

Arab Journal of Nuclear Sciences and Applications

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The DC gas discharge is established between coaxial cylindrical stainless steel electrodes. The coaxial cylindrical DC discharge device consists of an outer grid cathode and inner rods anode with 4 mm gap between them. This experimental study is focused on the effect of gas pressure and electric field strength on breakdown voltage. There is a balance between the electron attachment and first ionization collision, so the Second Townsend emission is the responsible for maintain the discharge. The I-V characteristic curves for different pressures of hydrogen gas indicate that the highest current appears for the highest gas pressure. The gas breakdown voltage varies as a product of Pd and Townsend's coefficients depends on gas pressure and E/P, where E is the electric field and P is the gas pressure.

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Section: Introductionmentioning

confidence: 99%

Characterization of Electrical Breakdown for Low and High Pressure Hydrogen Gas in Coaxial Virtual Cathode Device

Shagar

Ebrahim

Al-Halim

et al. 2018

Arab Journal of Nuclear Sciences and Applications

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“…The electrical breakdown of gases has been, since long time, the subject of many studies [1][2][3][4]. The interest in studying the magnetic field effect on the characteristics of electrical breakdown and on the properties of a Townsend discharge is motivated by a necessity of gaining a better understanding of the complex mechanisms of gas discharge phenomena and also because the B-field may contribute favorably for dealing with practical problems associated with the use of this kind of discharge for plasma processing technologies [5,6].…”

Section: Introductionmentioning

confidence: 99%

Longitudinal magnetic field effect on the electrical breakdown in low pressure gases

Filho¹,

Maciel²,

Pessoa³

et al. 2004

Braz. J. Phys.

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The electrical breakdown has been investigated for low-pressure argon and nitrogen discharges under the influence of an external longitudinal magnetic field. Plane-parallel aluminum electrodes (5 cm diameter) separated by a variable distance d (4.0 cm < d < 11.0 cm) were sustained with a dc voltage (0 < V < 1 kV). A Helmholtz coil was used to produce an uniform magnetic field(B) parallel to the discharge axis. Paschen curves were obtained and the secondary electron emission coefficient (γ), the first Townsend ionization coefficient (α) and the ionization efficiency(η), were plotted with respect to the variation of the reduced field (E/P). To observe the effect of the magnetic field these curves were plotted for fixed values of B=0 and B=350 Gauss. As consequence of the longitudinal magnetic field, the free paths of the electrons in the Townsend discharge are lengthened and their lateral diffusion is reduced, thus reducing electron losses to the walls. The data presented in this paper give a quantitative description of the B-field effect on the Townsend's coefficients and overall it is concluded that the DC electrical breakdown of the gases is facilitated if a longitudinal magnetic field is applied along the discharge axis.

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“…It allows us to use a time independent electron energy distribution function as discussed in [24]. Then the relevant steady state Boltzmann equation for f(ε) takes the form [15,16] (1) (2) where e, m and ε are the electron charge, mass and energy, respectively; T is the medium temperature. The effective electron atom energy exchange frequency in elastic collisions M, the atomic mass [15,16]).…”

Section: Electron Energy Distributionmentioning

confidence: 99%

“…Second, a coherent nature of electron scattering at spatially correlated heavy particles must be taken into account, which results in the electron momentum transfer frequency renormalization [15,16].…”

Section: Introductionmentioning

confidence: 99%

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Electronic transport coefficients and electric breakdown in condensed helium

Belevtsev

2015

High Temp

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The kinetic Boltzmann equation is applied to determine the electron energy distribution function in condensed helium over a wide range of pressures and temperatures. Account is taken of all the effects influ encing the electron kinetics in dense media. The electron multiplication rates and basic electron transport coefficients in condensed helium at atmospheric and elevated pressures have been determined. Starting from the streamer theory, the limiting breakdown characteristics of condensed helium are calculated. The theoret ical findings are compared with available experimental data. For liquid helium the long standing fundamen tal problem is first solved of the intrinsic dielectric strength determined exclusively by the electron processes in a liquid itself rather than in gaseous bubbles formed at the prebreakdown stage. Comparison with experi mental data allows also answering the question of how the voltage application duration and contaminants affect the breakdown characteristics of liquid helium.

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The Townsend coefficient of ionization in dense gases and fluids

Cited by 27 publications

References 14 publications

Characterization of Electrical Breakdown for Low and High Pressure Hydrogen Gas in Coaxial Virtual Cathode Device

Characterization of Electrical Breakdown for Low and High Pressure Hydrogen Gas in Coaxial Virtual Cathode Device

Longitudinal magnetic field effect on the electrical breakdown in low pressure gases

Electronic transport coefficients and electric breakdown in condensed helium

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