摘要:

AbstractFluctuations of the electric field, the charged particle density, the electron temperature and the plasma potential are simultaneously measured by a probe in the positive column of helium glow discharge at a few torr gas pressure by exciting a small amplitude ionization wave. It is proposed that these values can be determined by analyzing the probe current.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150280602

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe properties of the plasma of an underexpanded jet in air were examined by optical and by probe methods as described in a previous paper (Contrib. Plasma Phys.27(1987) 203). The jet was produced by an erosion plasmatron with xenon‐filling operating in a single‐pulse regime. Now, independent measurements of the space‐time development of the electron density by microwave interferometry are described. The results of cut‐off and phase shift measurements are in agreement with those obtained by probe diag

ISSN:0863-1042    

DOI:10.1002/ctpp.2150280603

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractElectron energy distribution functions and mean collision frequencles for the uniform bulk plasma of establishedrfdischarges in He/CO have been obtained by solving the time dependent Boltzmann equation. The results, which are of importance for plasma processing and laser technology, show that already small CO admixtures to He remarkably changes the periodic behaviour of the energy distribution of the electrons by drastical enhancement of the collisional energy dissipation effectiveness in the mixture. These changes can be interpreted on the basis of a lumped energy dissipation frequency in all electron collisions which is determined by the atomic data of the electron collision processes as well as by the admixture fractions and which drastically increases with increasing CO admixture. The degree of modulation of the energy distribution in different parts of the electron energy space and its population on the time average at higher energies are determined by the relation between therffield frequency and the mentioned lumped energy dissipation frequency.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150280604

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe well known diffusion theory of the positive discharge column is extended considering a plasma which burns between two coaxial cylindrical walls. Recent experimental investigations carried out with the goal to enlarge the fluxes of ultraviolet radiation in fluorescent lamp tubes motivate such an extension. Indeed, an enhancement of the efficacy could be found installating a glass rod along the tube axis which acts as an additional recombination surface. In order to understand this effect also a description of the radial plasma behaviour, especially that of the electron density, and of the necessary charged particle production by ionization is of interest. The paper reports about such an extension, including a representation of a suitable numerical solution approach and a discussion of the results.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150280605

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

摘要:

AbstractThe instability in a horizontal layer of a partially ionized self gravitating plasma has been studied to include simultaneously the effects of Hall currents, viscosity and finiteness of Larmor radius (FLR). The ambient magnetic field is assumed to be uniform and vertical. Proper solutions have been obtained through the variational methods for a semi‐infinite plasma in which the density has an exponential gradient along the vertical. The dispersion relation obtained has been solved numerically and it is found that the growth rate of unstable perturbations decreases with the effects of viscosity, neutral gas friction and FLR. The influence of effects of viscosity, neutral gas friction and FLR are consequently stabilizing. It is found that the Hall currents have a destabilizing influence as the growth rate is found to increase with this effec

ISSN:0863-1042    

DOI:10.1002/ctpp.2150280606

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY

ISSN:0863-1042    

DOI:10.1002/ctpp.2150280601

出版商:WILEY‐VCH Verlag    

年代:1988

数据来源: WILEY