The negative end of cold cathode glow discharges

Emeléus, K. G.

doi:10.1088/0022-3727/14/12/006

Cited by 20 publications

(9 citation statements)

References 42 publications

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“…The foregoing applies only to non-attaching gases, and when positive columns in attaching gases such as oxygen, iodine and SF6 are considered, additional effects including electron attachment and detachment, and ion-ion recombination, must be taken into account. The effects of negative ions in glow discharges have been summarised by Emeleus and Sayers (1938), Emeleus and Woolsey (1970) and Massey (1976). One of several significant differences between glows in attaching and non-attaching gases is the greater tendency for constriction of the positive column to occur in attaching gases.…”

Section: Introductionmentioning

confidence: 99%

Diffuse and constricted glow discharges in SF₆

Ogle

Woolsey

1987

J. Phys. D: Appl. Phys.

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SF6 glow discharges have been investigated for currents up to 20 mA, in the pressure 'range 0.1 to 10 Torr. As the pressure is increased, the discharge changes from an abnormal glow with a diffuse positive column to a normal glow with a constricted positive column. The diffuse discharges have positive voltagecurrent characteristics, while the characteristics of the constricted discharges are negative. From measurements of axial potential distribution and radial profiles of gas temperature in the positive column, radial profiles of f / N (electric fieldigas number density) were determined. E/N falls off from the axis to the wall, and the profiles show that the radial limit of the positive column for both diffuse and constricted discharges corresponds closely to the position where f / N = (f/N),, the value (362Td) where the rates of ionisation and attachment in SF6 are the same.The E / N measurements have been used, together with established electron and ion transport data for SF6 and a set of continuity equations for the electrons and ions, to determine radial density profiles for electrons, positive ions and negative ions in several SF6 diffuse and constricted positive columns.

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Section: Introductionmentioning

confidence: 99%

Diffuse and constricted glow discharges in SF₆

Ogle

Woolsey

1987

J. Phys. D: Appl. Phys.

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“…The motion of electrons in the cathode sheath region is notoriously difficult to treat theoretically due to the state of non-equilibrium between the electrons and the electric field (Segur et a1 1983, Emeleus 1981. Energy gained by the electrons from the field in the sheath is not usually matched by the energy lost by inelastic collision processes.…”

Section: Introductionmentioning

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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“…Experimental measurements of the EEDF in the NG indicate that electrons may be classified into two groups, trapped (plasma} electrons and a high-energy group referred to here as a beam [33,34]. (In [33], "beam" electrons refer to those electrons which pass through the CF without a single inelastic collision; under our simulation conditions, very few electrons escape inelastic collisions in the CF.…”

Section: Treatment Of Negative Glowmentioning

confidence: 99%

Self-consistent Monte Carlo simulation of the cathode fall including treatment of negative-glow electrons

1992

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We present results from a self-consistent Monte Carlo simulation of the cathode fall (CF) of a dc glow. The simulation consists of following electron and ion trajectories under the influence of the electric field which is calculated from Poisson s equation using the ion and electron densities. The collision cross sections are greatly simplified in order to facilitate understanding of the physical mechanisms which dominate the CF. With this aim, we explicitly sample the electron distribution function and discuss its properties. We also show that it is feasible to simulate the CF in isolation from the negative glow (NG) as long as backscattering from the NG is accounted for. Finally, we take into account the plasma (trapped) electrons in the NG, and formulate a model of the CF-NG boundary region through use of the plasmasheath equation. We find that the length of the boundary region grows with the NG density, and that there is a corresponding increase in the fraction of the ion flux which enters the CF as opposed to being created in it. For reasonable values of the NG density, we find this fraction to be as high as 25%.

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The negative end of cold cathode glow discharges

Cited by 20 publications

References 42 publications

Diffuse and constricted glow discharges in SF₆

Diffuse and constricted glow discharges in SF₆

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

Self-consistent Monte Carlo simulation of the cathode fall including treatment of negative-glow electrons

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The negative end of cold cathode glow discharges

Cited by 20 publications

References 42 publications

Diffuse and constricted glow discharges in SF6

Diffuse and constricted glow discharges in SF6

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

Self-consistent Monte Carlo simulation of the cathode fall including treatment of negative-glow electrons

Contact Info

Product

Resources

About

Diffuse and constricted glow discharges in SF₆

Diffuse and constricted glow discharges in SF₆