The townsend coefficient and runaway of electrons in electronegative gas

Boichenko, A. M.; Ткачев, А. Н.; Yakovlenko, S. I.

doi:10.1134/1.1648292

Cited by 15 publications

(24 citation statements)

References 4 publications

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“…The results of the calculations in [19] show that for a sufficiently large reduced field strength (E/p> 94·V/(cm Torr)) and sufficiently large interelectrode distance (d> α −1 i ), the anticipated Townsend ionization regime actually takes place. The main characteristics of the regime (Fig.…”

Section: −1mentioning

confidence: 93%

“…We will discuss below the results of simulations of multiplication process for He [17-19, 22, 24], Ne [25], Xe [18,19,22], N 2 [21,22] and SF 6 [19], which were performed within the framework of a model described in [34,35]. In these simulations an electron motion in a flat gap (between two planes spaced by a distance dand driven by the applied voltage U ) was considered.…”

Section: Used Modelsmentioning

confidence: 99%

“…In view of the competition between the electron attachment and multiplication processes, it is not clear whether the concept of the Townsend coefficient is adequate in application to such gases, which are widely used in various discharges, in particular, for pumping exciplex and chemical lasers. The electron multiplication and runaway in SF 6 were considered in [19]. For this gas the characteristics of the electron collisions are well known.…”

Section: −1mentioning

confidence: 99%

“…For helium the following magnitudes on the basis of the model described in ref [17][18][19] were calculated (see Fig. 14a):…”

Section: Efficiency Of Various Inelastic Actsmentioning

confidence: 99%

“…Contrary to this viewpoint we will show that the mechanisms of the electron runaway in gas-discharge plasma and in fully ionized plasma differ radically. Namely, both the numerical simulations and analytic consideration show that in the case of a gas-discharge plasma with sufficiently large distances between anode and cathode there is no acceleration of quite all electrons [17][18][19][20][21][22][23][24][25]. If the interelectrode distance is sufficiently large, the predominant number of electrons ionizes the gas in the Townsend mode at arbitrarily high field strength.…”

Section: Introductionmentioning

confidence: 99%

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Runaway of electrons in dense gases and mechanism of generation of high-power subnanosecond beams

Ткачев

Yakovlenko

2004

Open Physics

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New understanding of mechanism of the runaway electrons beam generation in gases is presented. It is shown that the Townsend mechanism of the avalanche electron multiplication is valid even for the strong electric fields when the electron ionization friction on gas may be neglected. A non-local criterion for a runaway electron generation is proposed. This criterion results in the universal two-valued dependence of critical voltage U cr on pd for a certain gas (p is a pressure, d is an interelectrode distance). This dependence subdivides a plane (U cr , pd ) onto the area of the efficient electron multiplication and the area where the electrons leave the gas gap without multiplication. On the basis of this dependence analogs of Paschen's curves are constructed, which contain an additional new upper branch. This brunch demarcates the area of discharge and the area of e-beam. The mechanism of the formation of the recently created atmospheric pressure subnanosecond e-beams is discussed. It is shown that the beam of the runaway electrons is formed at an instant when the plasma of the discharge gap approaches to the anode. In this case a basic pulse of the electron beam is formed according to the non-local criterion of the runaway electrons generation. The role of the discharge gap preionization by the fast electrons, emitted from the plasma non-uniformities on the cathode, as well as a propagation of an electron multiplication wave from cathode to anode in a dense gas are considered.

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Section: −1mentioning

confidence: 93%

Section: Used Modelsmentioning

confidence: 99%

Section: −1mentioning

confidence: 99%

“…For helium the following magnitudes on the basis of the model described in ref [17][18][19] were calculated (see Fig. 14a):…”

Section: Efficiency Of Various Inelastic Actsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Runaway of electrons in dense gases and mechanism of generation of high-power subnanosecond beams

Ткачев

Yakovlenko

2004

Open Physics

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Simulation of runaway electron inception and breakdown in nanosecond pulse gas discharges

Zhang

Wang

et al. 2015

Laser Part. Beams

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Nanosecond pulse discharges can provide high reduced electric field for exciting high-energy electrons, and the ultrafast rising time of the applied pulse can effectively suppress the generation of spark streamer and produce homogeneous discharges preionized by runaway electrons in atmospheric-pressure air. In this paper, the electrostatic field in a tube-plate electrodes gap is calculated using a calculation software. Furthermore, a simple physical model of nanosecond pulse discharges is established to investigate the behavior of the runaway electrons during the nanosecond pulse discharges with a rise time of 1.6 ns and a full-width at half-maximum of 3–5 ns in air. The physical model is coded by a numerical software, and then the runaway electrons and electron avalanche are investigated under different conditions. The simulated results show that the applied voltage, voltage polarity, and gas pressure can significantly affect the formation of the avalanche and the behavior of the runaway electrons. The inception time of runaway breakdown decreases when the applied voltage increases. In addition, the threshold voltage of runaway breakdown has a minimum value (10 kPa) with the variation of gas pressure.PACS: 52.80.-s

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Numerical simulation of runaway electrons generation in sulfur hexafluoride

Levko¹,

Krasik²

2012

Journal of Applied Physics

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The results of the numerical simulation of the generation of runaway electrons in sulfur hexafluoride are presented. It is shown that the emission of the runaway electrons occurs from the cathode and its vicinity. The generation of these electrons is terminated because of the formation primarily by negative ions of a virtual cathode which causes the field emission to be screened. The simulations showed that the virtual cathode consists mainly of negative ions and cannot be an effective source of runaway electrons. In addition, the results of the simulations showed that the parameters of the runaway electrons depend on the amplitude and rise-time high-voltage pulse and gas pressure. V

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The townsend coefficient and runaway of electrons in electronegative gas

Cited by 15 publications

References 4 publications

Runaway of electrons in dense gases and mechanism of generation of high-power subnanosecond beams

Runaway of electrons in dense gases and mechanism of generation of high-power subnanosecond beams

Simulation of runaway electron inception and breakdown in nanosecond pulse gas discharges

Numerical simulation of runaway electrons generation in sulfur hexafluoride

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