摘要:

AbstractIt was demonstrated in many experiments, that the expansion of the dense plasma of a vacuum arc spot goes along with an acceleration of multiply charged ions in the direction of the anode. The resulting plasma jet is analysed in a stationary and quasi‐onedimensional model, that accounts for virtually all existing explanations. The corresponding system of multifluid equations includes singular points. The model is evaluated for two versions, that are suited to describe the cathodic jet and for which the singular points can be treated. The agreement with the experimentel results is satisfactory. It turns out, that the acceleration of the ions is mainly due to the electron‐ion friction. The results indicate, that the study of the plasma jet is a suitable tool to get a more detailed knowledge of the cathode s

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270502

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractOn the basis of an improved cascade model a multi‐group theory for studying the electron kinetics in the cathode region of a glow discharge and in hollow cathodes is developed. The secondary electrons newly created by ionization are taken into account. The electrons are divided in groups with respect to the interval where they were created or where they made an inelastic collision. The inelastic collisions and the forward scattering are assumed to dominate. The mean energies of two neighbouring groups are taken to be different by the ionization energy or by parts of it. For the flux densities of the various electron groups a set of ordinary first order differential equations and corresponding boundary conditions are obtained and solved for He. These formulae are valid for any electric potentials. The results relatively well agree with those of Monte Carlo simulations. The first Townsend ionization coefficient differs substantially from that resulting from the Townsend formula. The velocity distribution function spatially varies and contains several groups of fast electrons. Using the detour factor the angular scattering can be included in the calculation

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270503

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe exchange‐correlation part (xc) to the free energy is numerical evaluated in the RPA at arbitrary degree of degeneracy. The results are compared with numerical data of easy‐to‐use analytic fit‐formulas or Padé approximants of thexc‐term. All together results show very high accuracy at extremly high densities (rs≈ 1). The agreements disappear between the several formulas for increasing Brueckner parameterrs. Numerical results for thexc‐potentials (pressure and chemical potential) at finite temperatures for an electron‐ion system are given. Thexc‐part of the ground state energy of our electron‐ion model is compared with the ground state energy for metallic hydrogen and with Mont

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270504

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractIonization cross sections of fragment ions of CF4, C2F6, C3F8,n‐C4F10, C2F4, 1‐C4F8, SiF4, COF2. CHF3were determined in dependence on electron energy up to 125 eV by means of a quadrupol mass spectrometer. Tails at the low energy part of the characteristics are interpreted as a result of kinetic energy depending on molecular weight of fragments. Parent ions are only detected for chemically unsaturated compounds showing characteristic curves of ionization efficiency. Total cross sections obey the additive r

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270505

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractAs pointed out in a previous paper, stable spherical plasma configurations can be produced by pulsed injection of a plasma into an ambient gas. It is shown here that the observed long plasma lifetime of several milliseconds is in agreement with collisional‐radiative recombination theories. We used the modified diffusion approximation by Biberman et al. involving thermal non‐equilibrium, recombination heating of electrons, heat conduction, radiation and other details. Under the assumption of a pure xenon plasma, the calculated plasma lifetime is even longer than the observed one. This discrepancy can be explained by the presence of molecules and turbulent mixing with the outer gas, which are not considered in the recombination calculat

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270506

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270501

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY