Electron energy distributions in plasmas IV. Oxygen and nitrogen

The Druyvesteyn method of measuring electron energy distributions in low pressure plasmas has been applied to cold-cathode direct current glow discharges in oxygen and nitrogen at pressures in the range 0.010 to 0.050 mm Hg. Two discharge modes occurred in both gases. Mass spectrometer measurements showed that in nitrogen only N 2 + was present but in oxygen the ions O - , O 2 - , O + , O 2 + , were all present. O - and O 2 + concentrations were about equal in magnitude and formed over 90 % of the ions present. Electron energy distributions in the positive column showed three groups in oxygen and nitrogen. The data available from the oxygen discharge are consistent with the lowest energy peak being a manifestation of a large negative ion concentration ( n - / n e = 20).

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A hybrid model for particle transport and electron energy distributions in positive column electrical discharges using equivalent species transport

Journal of Applied Physics ◽

10.1063/1.360592 ◽

1995 ◽

Vol 78 (10) ◽

pp. 5909-5918 ◽

Cited By ~ 8

Author(s):

Fred Y. Huang ◽

Mark J. Kushner

Keyword(s):

Electron Energy ◽

Hybrid Model ◽

Particle Transport ◽

Positive Column ◽

Electrical Discharges ◽

Energy Distributions ◽

Species Transport

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Global model analysis of negative ion generation in low-pressure inductively coupled hydrogen plasmas with bi-Maxwellian electron energy distributions

Physics of Plasmas ◽

10.1063/1.4914088 ◽

2015 ◽

Vol 22 (3) ◽

pp. 033506 ◽

Cited By ~ 19

Author(s):

Sung-Ryul Huh ◽

Nam-Kyun Kim ◽

Bong-Ki Jung ◽

Kyoung-Jae Chung ◽

Yong-Seok Hwang ◽

...

Keyword(s):

Electron Energy ◽

Low Pressure ◽

Model Analysis ◽

Global Model ◽

Negative Ion ◽

Energy Distributions ◽

Inductively Coupled ◽

Hydrogen Plasmas ◽

Ion Generation

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Electron energy distributions in the low-pressure mercury-vapour discharge: the Langmuir paradox

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1968.0074 ◽

1968 ◽

Vol 304 (1476) ◽

pp. 87-98 ◽

Cited By ~ 13

Keyword(s):

Distribution Function ◽

Energy Distribution ◽

Electron Energy ◽

Langmuir Probe ◽

Positive Column ◽

Probe Method ◽

Maxwellian Distribution ◽

Mercury Vapour ◽

Energy Distributions ◽

Plasma Oscillations

Electron energy distributions have been measured in mercury-vapour discharges by means of the Langmuir-Druyvesteyn probe method. These measurements show that the discharge can be conveniently divided into two contrasting regions-the first, very near the cathode, in which strong beam-plasma interaction occurs, resulting in the excitation of strong plasma oscillations and the scattering of the electron beam from the cathode to produce a uniform monotonically decreasing distribution function; the second region, or positive column, occupies almost the whole length of the discharge tube and in this region the electron energy distribution is not Maxwellian, there being no energy-exchanging process operative in the column, in the wall sheath or in the probe sheath. Non-uniformities in the energy distribution originating near the cathode persist along the 170 cm length of the column. In a part of this column a simple Langmuir probe curve (In i - V ) has been obtained which is superior to any which has previously been published as evidence for the existence of a Maxwellian distribution. However, the more sensitive Druyvesteyn plot of d 2 i /d V 2 against V shows that even this distribution is non-Maxwellian. It must, therefore, be concluded that the Langmuir probe method has never satisfactorily established the existence of a Maxwellian distribution in a low current discharge.

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