On the Anomaly of the Electrical Field Strength in the Magnetized Positive Column of Glow Discharges at Small Currents

Deutsch, Hans‐Peter; Klagge, S.

doi:10.1002/ctpp.19830230402

Cited by 2 publications

(2 citation statements)

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“…Experimental results with varying degrees of insulating walls have shown significant discrepancies with theory. For example, in several experiments with positive column discharges the apparent transverse diffusion coefficient initially increases with increasing magnetic field and then begins to decrease approximately as predicted by eq (65) [ 112 , 135 , 136 ]. One reason for this effect is that at zero magnetic field and at low enough gas densities λ u /Λ is large enough such that the electron energy distribution and “temperature” vary significantly with radius as discussed in section 4.1.2.…”

Section: Applications Of Models Of Ambipolar Diffusionmentioning

confidence: 91%

“…When an axial magnetic field is raised such that β e ≽ 1 the effective energy relaxation length and the radial transport of electron energy are significantly decreased, the average ionization rate coefficient is reduced, and the axial E a / n required to maintain the discharge increases. Models of the first maximum in E a / n have also included the effects of metastables [ 136 ]. The role of ionization waves has been debated [ 112 , 137 ].…”

Section: Applications Of Models Of Ambipolar Diffusionmentioning

confidence: 99%

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The diffusion of charged particles in collisional plasmas: Free and ambipolar diffusion at low and moderate pressures

Phelps¹

1990

J. RES. NATL. INST. STAN.

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The interpretation of measurements of the properties of weakly ionized plasmas in terms of diffusion of electrons and ions is reviewed both critically and tutorially. A particular effort is made to tie together various aspects of charged particle diffusion phenomena in quiescent, partially ionized plasmas. The concepts of diffusion length and effective diffusion coefficient and the treatment of partially reflecting boundaries are developed in the limit of the space-charge-free motion of the electrons or ions. A simplified derivation of the screening length for space charge electric fields is followed by a review of the conventional derivation of diffusion in the ambipolar limit. A discussion of the scaling parameters of the ratio of the diffusion length to the screening length and the ratio of the diffusion length to the ion mean-free-path leads to a map used to correlate published models covering the complete range of these parameters. The models of measurements of the diffusion of electrons, several types of positive ions, and negative ions are reviewed. The role of diffusion in the decay of charged particle densities and wall currents during the afterglow of a discharge is then considered. The effects of collapse of the space charge field and of diffusion cooling are reviewed. Finally, the application of the diffusion models to a number of different discharges is discussed.

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Section: Applications Of Models Of Ambipolar Diffusionmentioning

confidence: 91%