摘要:

AbstractThe modifications in the time‐averaged plasma particle distribution functions in the presence of a large amplitude electromagnetic wave are studied. It is shown that the ponderomotive force is responsible for tail formation, non‐zero particle currents and heat fluxes. Explicit results, which describe those effects, are deri

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230502

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractA system of nonlinear equations derived in a previous paper which describes the evolution of nonresonant waves in beam‐plasma systems is solved numerically. It is given a physical interpretation of essential features of the nonresonant beam‐plasma instability. The significant influence of higher harmonics on the evolution of an electron beam in the plasma which is modulated on a nonresonant unstable frequency, is investigated. The interaction of unstable nonresonant and resonant waves in beam‐plasma systems is examined. It is shown that the evolution of resonant waves can be essentially influenced by an initial modulation of the beam on an unstable non‐resonant frequency. The role of an initial velocity modulation of the beam for the influence of the wave spectrum is demon

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230503

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractA system of nonlinear equations derived in a previous paper which describes the evolution of the beam‐plasma instability in strong dissipative plasmas is solved numerically. It is shown that there are three characteristic solutions of the system of equations: the resonant dissipative instability, the nonresonant instability with strong dissipation and the nonresonant dissipative instability. A physical interpretation of essential features of these instabilities is given. The interaction of resonant and nonresonant waves in the system electron beam‐strong dissipative plasma is examined. Some conclusions for the transport problem of electron beams in strong dissipative plasmas are obtained in this pa

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230504

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe paper deals with the mathematical structure of the general solution and the selection of the physical relevant solution of the hierarchy resulting from the electron Boltzmann equation by the Legendre polynomial expansion for a weakly ionized plasma with elastic and exciting collisions and under the action of an electric field. At first the properties of the general solution for the two and four term approximation of the distribution function are analyzed and then the study is extended to arbitrarily even order of the hierarchy using the theory of weakly and strongly singular differential equation systems for the investigation of the solution behaviour of the truncated hierarchy at small and at large energies, respectively. In this way, especially the free parameters of the non‐singular part of each general solution, which is obtained for small and large energies and is of interest for the construction of the desired solution, could be found, and the procedure for their final determination is explained. A first illustrative example is given of the application of these studies for the determination of the velocity distribution function of the electrons in four term approximation for a model plasm

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230505

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe inverse matrix method is a variation of the Pearce method for numerically solving the Abel integral equation in plasma spectroscopy. Differed from the original method, the matrix method allows a direct determination of radial intensity profiles without iterative calculation from the zone of the plasma edge. From the tests through numerical simulations, it is found that this method has the higher accuracy than the original method by reducing the errors caused by iterative calculations. Since no smoothing procedure is included, the matrix method is vulnerable to receive the effects of random scattering. However, when appropriate smoothing is made, this method becomes as useful as the other methods. The Nestor‐Olsen and Barr methods are also tested for compariso

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230506

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractIn the positive column of hydrogen low pressure gas discharges the radial temperature profil was measured by an interferometric method. A Michelson‐interferometer in combination with an He—Ne‐laser was used. In the range from 532 to 1330 Pa and 25 to 100 mA for a water cooled tube of inner diameter of 20.5 mm axis temperatures from 340 to 500 K with a nearly parabolic profil were found. Rotational temperatures from the Fulcher‐bands were systematically lower ab

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230507

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe use of different plasma models for composition calculations of nonideal plasmas can result in very different electron concentrations for the same experimental situation characterized e.g. by the measured temperature and pressure. This gives rise to misunderstandings at comparison of theoretical and experimental results. For extreme conditions i.e. in the region of the supposed plasma phase transition results of solid state physics give us the possibility to rule out some plasma models.

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230508

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe CCl4plasma decomposition and the etching of SiO2and Al by the CCl4plasma is investigated with the aid of emission intensityIλ of such species as Cl2, CCl, Cl and CO, which are influenced systematically by the etching process. A time independent electron density (ne≈ 2 · 108−1 · 1010cm−3, dependent on plasma conditions) is measured by microwave diagnostics. The ratioIλ/neandIλ/Ireference' resp. (Ireference=IHelium) is a relative measure of concentrations. The ratioIcl2/Icclis very sensitive against CCl4‐decomposition and etching processes of SiO2and Al. Its changes during the etching process of SiO2and Al in a CCl4plasma are

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230509

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractFrom an electrodynamic and simple quantum‐mechanical point of view a model is proposed which explains the phenomena of minimum arc current as well as the formation and extinction of tiny emitting sites interacting together in cold cathode spots (called type A) on the base of a specific coupling between the tunnelling “average” electrons and the metal bulk phonon field. The model seems to be especially applicable to such experimental conditions where typical trumpetlike microcraters with pronounced rims with diameters in the range 0.5—1 μm are left by microspot ensembles on the cathode surface.The model yields emitting‐site lifetimes, currents, current densities and radii in the order of τps⋍\documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt {3M/m} $\end{document}τ0⋍ 10−11sec,Imin= 4π ℏ\documentclass{article}\pagestyle{empty}\begin{document}$ \sqrt {n/\mu _0 m} $\end{document}⋍ 0.4 A,j=nevs⋍ 4 · 1013A/m2andra⋍ 2c/ωPl⋍ 30 nm (τps…lifetime of short wave phonons,M… atom mass,m… electron mass, τ0… mean free collision time of Fermi electrons at room temperature,n… conduction electron density in the metal bulk,vs… metal bulk sound velocity,c… light velocity, ωPl… metal bulk plasma frequency (values for copper). The lifetime and the interaction diameter of an emitting site (event) ensemble are derived to τpl⋍(M/m) τp⋍ 3 nsec and Λpl= νsτpl⋍ 1

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230510

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230501

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY