Experimental Measurements on the Current Balance at the Cathode of a Cylindrical Hollow Cathode Glow Discharge

Helm, H.

doi:10.1002/ctpp.19790190405

Cited by 17 publications

(7 citation statements)

References 28 publications

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“…The form of the EDEF in practice is determined by the energies of the electrons released from the cathode via secondary emission processes resulting from ion, metastable and photon impacts. It has been shown by Helm (1979), however, that secondary emission by ion impact is the dominant mechanism in helium discharges. Secondary-electron emission from various metals resulting from helium-ion impacts has been investigated by Carter and Colligon (1968).…”

Section: N -( E -Z0)/(2 6 E )mentioning

confidence: 99%

A simulation of electron motion in the cathode sheath region of a glow discharge in helium

Carman

Maitland

1987

J. Phys. D: Appl. Phys.

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Electron motion in the cathode sheath region of a glow discharge in helium has been simulated using a one-dimensional computer model. Distribution functions for the electron flux across the cathode sheath have been calculated for fourteen values of the cathode fall between 150 and 1700 V. Macroscopic variables including the Townsend ionisation coefficient, multiplication coefficient and mean electron energy have been determined for the cathode fall range 150-1000 V. It is shown that the proportion of electron flux crossing the cathode sheath without collisions increases as the cathode fall is raised. For a cathode fall between 400 and 1400 V, the electron flux at the cathode sheath/negative glow boundary possesses beam-like characteristics. Beyond 1400 V, the largest component, in the electron flux distribution, to reach the sheath boundary is the collision-free group. These electrons enter the negative glow with energies corresponding to the cathode fall potential, and are practically mono-energetic. The authors propose that this is a suitable criterion to refer to the entire cathode sheath/negative glow region as an 'electron-beam' glow discharge.

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Section: N -( E -Z0)/(2 6 E )mentioning

confidence: 99%

A simulation of electron motion in the cathode sheath region of a glow discharge in helium

Carman

Maitland

1987

J. Phys. D: Appl. Phys.

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“…The 'beam' component is due to high-energy secondary electrons emitted from the cathode and accelerated, without collisions, by the strong electric field in the cathode fall. In the case of a helium glow discharge, secondary electrons are mainly generated by ion bombardment (Helm 1979). The 'beam' component is only I-3% of the total distribution even under the DC condition (Gill and Webb 1977), for which many secondary electrons are generated by ion bombardment and also a very scrong electric field is formed in front of the cathode.…”

Section: Energy Distributionsmentioning

confidence: 99%

Self-consistent Monte Carlo modelling of RF plasma in a helium-like model gas

Date

Kitamori

Sakai

et al. 1992

J. Phys. D: Appl. Phys.

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A self-consistent modelling and simulation technique of RF nonequilibrium plasmas using a Monte Carlo method is presented. Under the condition that the product of the gas pressure and the gap length is small and/or the local electric field changes rapidly, as is commonly the case with RF plasmas, the electron energy distribution shows a nonequilibrium effect against the local electric field. The kinetics of electrons and ions is calculated by a Monte Carlo method which enables the authors to deal fully with the nonequilibrium effect. The electric field in the plasma is self-consistently determined by solving Poisson's equation. With a particle model, the statistical fluctuation tends to be large in the sheath in which the number densities of electrons and ions are low. A scaling technique which enables the authors to diminish the fluctuation, and therefore the instability of the simulation is used. The simulation method is applied to an RF plasma in an He-like model gas and the results suggest that this model can adequately simulate RF plasmas.

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“…In ordinary plane cathode discharges the role of ultraviolet (UV) photons in the maintenance of the discharge was found to be relatively unimportant [18]. On the other hand, in HC discharges the high importance of photoelectrons emitted by the cathode due to UV radiation from the discharge has been experimentally demonstrated [19,20].…”

Section: Introductionmentioning

confidence: 99%

A Study of the Motion of High-Energy Electrons in a Helium Hollow Cathode Discharge

Donkó

1993

Zeitschrift Für Naturforschung A

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The motion of high-energy electrons was studied in a helium hollow cathode discharge using Monte Carlo simulation. The calculations were carried out in the pressure range of 2-10 mbar. The length of the cathode dark space (CDS) was determined by simulation in an iterative way using experimental voltage-current density characteristics of the discharge. At the lowest helium pressure (2 mbar) the concentration of high-energy electrons was found to be the same at the CDS-negative glow boundary and at the midplane of the discharge while at 8 mbars it was found to be by 1-2 orders of magnitude smaller. The results of our calculations support the existence of "oscillating" electrons. The probability of 1, 2 and 3 transfers through the negative glow (NG) for primary electrons was found to be 37%, 11 % and 2%, respectively, at 2 mbar pressure. The spatial distribution of ionizations and the angular distribution of electron velocity at the CDS-NG boundary were also investigated. The pressure dependence of the current balance at the cathode was obtained, and the results indicate that with decreasing pressure other secondary emission processes than ion impact become important in the maintenance of the discharge.

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Experimental Measurements on the Current Balance at the Cathode of a Cylindrical Hollow Cathode Glow Discharge

Abstract: The contribution of positive ions, photons and metastable particles to the secondary emission of electrons from the c Show more

Cited by 17 publications

References 28 publications

A simulation of electron motion in the cathode sheath region of a glow discharge in helium

A simulation of electron motion in the cathode sheath region of a glow discharge in helium

Self-consistent Monte Carlo modelling of RF plasma in a helium-like model gas

A Study of the Motion of High-Energy Electrons in a Helium Hollow Cathode Discharge

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