ISSN:0863-1042    

DOI:10.1002/ctpp.2150360402

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe first coefficients in the orthogonal expansions of the velocity distribution functions with respect to Grad's tensorial (three‐dimensional) Hermite polynomials are shown to be proportional to ther‐modynamic fluxes, if the weight functions are local Maxwellians centered at the mean mass velocity and widened with a mean temperature. Balance equations for the stress tensors are established and reduced to linear algebraic systems under certain restrictions. Explicit solutions for the traces and the tracefree parts of the stress tensors are gi

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360403

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe radial change of the electron velocity distribution function and of related macroscopic quantities of the electrons are studied theoretically and experimentally in the positive column plasma of a neon dc low pressure glow discharge. The theoretical investigations are based on the solution of electron kinetic equations. The measurements of electron kinetic quantities are performed by using a single probe technique with automated recording. To avoid the strict treatment of the complicated radially varying electron kinetics in the microphysical description of the column plasma, various simplifications of the appropriate inhomogeneous kinetic equation have been adopted in the past. Recently a strict solution approach of this complex kinetic problem could be developed. Using this strict solution approach and experimentally determined electron kinetic quantities the approximation quality, obtained by applying various simplified approaches to treat the electron kinetics as the conventional homogeneous approach, the nonlocal approach and the local field approximation, is illustrated and critically evaluated in this paper.

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360404

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThe spatial distribution of ozone and of oxygen atoms was studied along the active and the passive zone of a dc discharge (positive column, pressure: p = (4 … 10) · 102Pa, current:I= 2 … 50 mA, flow rate:F= 5 … 100 sccm) in flowing oxygen. The composition of the final outputO2/O3‐mixture is controlled by relaxation processes in the passive reactor zone. It is affected sensitively by the total number density and the gas temperature in the afterglow. Steady states meaning reversible chemical quasi‐equilibria were observed and analysed extensively. Within a detailed kinetic model the formation of these equilibria can be explained quantitatively. The synthesis to ozone is controlled above all by the metastableO2(a1Δg) species, which modify drastically the results for the basic mechanism, considering theOatoms in the3P

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360405

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractAfter a review of more or less systematic approaches for normal as well as anomalous particle transport phenomena across a magnetic field, simplified macroscopic models are discussed. A reduced two‐field model for collision‐dominated low‐temperature plasmas is presented. Although it looks similar to its high‐temperature analogue (known as the Hasegawa‐Wakatani equations), it has significant peculiarities which are discussed in detail. Some basic results following from the reduced two‐field model, e.g. anomalous transport scaling close to the onset of collisional driftwave instability, ar

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360406

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractA new mathematical method is presented which allows a systematic construction of the radial profiles of emissivity, angular frequency, and temperature from a measured two‐dimensional intensity distribution functionI(λ,x) whose spectral part is determined by line shift and line broadening due the Doppler‐effect. The suitability of the method is demonstrated by test calculations and application to experimental

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360407

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper presents a contribution to bifurcation phenomena in scrape‐off layer modelling. The bifurcations are caused by the non‐monotonic temperature behaviour of the radiation characteristics of plasma impurities. Low‐frequency relaxation oscillations observed in divertor plasmas of the ASDEX Upgrade tokamak are analyzed and computed using a simple model for the dynamics of the impurity density and the electron temperature. The corresponding model equations are a special case of a general system of transport equations whose stability is analyzed. Bifurcations are calculated by solving autonomous and parametrically driven model equa

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360408

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY

ISSN:0863-1042    

DOI:10.1002/ctpp.2150360401

出版商:WILEY‐VCH Verlag    

年代:1996

数据来源: WILEY