摘要:

AbstractStarting from nonlinear evolution equations of a three‐dimensional extra‐ordinary wavepacket in a magnetized plasma and introducing a correlation function, equations are derived that describe interaction of a coherent low‐frequency magneto‐acoustic wave with a turbulent spectrum of high frequency extra‐ordinary waves. These equations are used to derive the dispersion relation for a low frequency magnetoacoustic wave in the presence of a spectrum of turbulent high frequency extra‐ordinary waves. In the narrow spectrum case, it is found that a small but finite spread in the spectrum of turbulence has a stabilizing influence on the instability which exists for vanishing spectral width. In the wide spectrum case, the effect of a weak turbulent spectrum of extra‐ordinary waves is to produce a slight shift in frequency of the coherent low frequency magneto‐acoustic wave and to damp or

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230302

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe question of the establishment of an almost complete Maxwellian energy distribution of the electrons in a given discharge plasma is of importance, especially under the aspect of a more convenient determination of transport and rate coefficients.In [5] an energy space averaged criterion for the establishment of such a structure of the electron energy distribution function in the stationary beam discharge plasma of molecular gases was formulated from a heuristic point of view.This paper investigates this question in detail starting from the adequate Boltzmann equation of such plasmas. Energy resolved conditions for the establishment of an almost complete Maxwellian distribution are derived from the kinetic equation. Using one of these conditions, the formal derivation of the mentioned averaged condition is performed and its limitations are shown. The fulfilment of the energy resolved and of the averaged conditions are illustrated and discussed using solutions of the kinetic equation in purely molecular hydrogen for two parameter sets yielding larger and smaller deviations of the real distribution function from the Maxwellian form.

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230303

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe energy and momentum balance equations for a potential wave in a monoenergetic electron beam‐plasma system are considered in the linear approximation, when the wave is in Čerenkov resonance with the beam particles. An energetic analysis of certain types of beam‐plasma instabilities is given. It is shown that the energy and momentum balance equations are consistent with the dispersion relation for all unstable waves. From this fact follows that the energy and momentum densities of all linear unstable waves in reactive beam‐plasma systems are equal to zero. An interpretation and a possible classification of beam‐plasma instabilities a

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230304

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractA problem of description of the electron component in the plasmachemical reactors of beamplasma type is examined. Conditions under which the electrons have a velocity distribution close to the Maxwellian one are elucidated. A hydrodynamic approach for description of the electron component in the Maxwellian regimes has been suggested instead of the kinetic approach developed by Winkler et al. [Beitr. Plasmaphys. 19 (1979) 319]. A method of calculation of the non‐Maxwellian additive to the electron distribution function is formulated, for the proposed hydrodynamic approach to prove. A critical analysis of computer results found by the kinetic approach is give

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230305

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractThe beat heating of a magneto‐plasma by two antiparallel electromagnetic waves at different temperatures is examined. The effects of plasma temperature, plasma electron collisions, plasma ion collisions and magnitude and direction of the magnetic field on the excitation of plasma electron waves and plasma ion waves are studied. A formula for the power absorption density of the plasma by using Maxwell's equations in conjuction with continuity and momentum equation. including collisions and pressure tensor terms, is derived. The contribution of the plasma temperature to the power absorption density, both at low and high beat frequencies, of the collisional and the non‐collisional magnetised plasmas is found very significant and is illustrated numerically. The inclusion of pressure tensor term in the momentum equation is also found to cause characteristic changes in the power absorption density of the plasma with the orientation of magnetic fi

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230306

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractIt is shown in this paper that the form of the electron concentration distribution along the radius of the positive column in an oxygen discharge depends on the relative concentration of negative ions α =n‐/nein the plasma.It is found that in discharges in electronegative gases everywhere along the radius of the positive column, where α>10, the electron concentration is equal to its value on the tube axis (plane electron distribution along the radius of the positive column).It is shown that an increase of the discharge current leads to the decrease of α and to the change of the distribution of profilenefrom plane to parabolic. However, weak laminar oxygen pumping along the positive column leads to more plane an electron concentration distribution because an increase of the negative ions concentration takes place. It is induced by the decrease of oxygen atoms density on account of their carrying out by the

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230307

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractDischarges between glazed electrodes forp= 2.67 kPa Ne + 1% N2andpd= 1.3 kPa cm (p= gas pressure,d= electrode distance) are investigated. They are sustained by a sine wave voltage of variable frequencyf. Measurements of the space time structure of the radiation emission provide information of the build up and quenching of discharges and of the structure of the fully developedac‐discharge.It is shown that the discharge types for the different values of frequency and amplitude of the sine wave sustaining voltage are dynamically developed Townsend and glow discharges. Forf≦ 4 kHz the optical structure and its temporal behaviour largely depends on the increment of the sustaining voltage. Forf≧ 20 kHz the axial structure of radiation emission is modified by the influence of consecutive discharges due to residual ions (f≌ 20 kHz) and metastable Ne(3P2)‐atoms (f>20 kHz) existing for several periods of sine wave. The Penning effect of metastable Ne‐atoms with N2molecules then produces start electrons for each discharge in a sequence which improve the initial conditions for the breakdown. Relations between space time structure and breakdown voltage as a function of frequencyfar

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230308

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractAn experimental and theoretical study of the interaction between Argon and a high‐energy short‐pulse electron beam is reported. A theoretical model describing the argon atom and molecule with ten effective levels and taking into account all the reactions that these levels may suffered is developped. A comparison, based on time resolved V.U.V. and visible fluorescences and electron density determination, between the theoretical and experimental results shows the ability of our model to describe the interaction in all the experimental range, 400

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230309

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractFundamentals of microscopical theory of the corona discharge are considered. Main mechanisms of generation and disappearance of charged and excited particles are discussed for the example of the helium discharge. An important role of pair ionizing collisions of metastable particles is indicated. Field configurations and distributions of charged and excited particles in the discharge gap are obtained, the corona voltage‐current characteristics are calculated. It is shown that the presence of nonlinear ionization processes may result in hysteresis phenomena. In particular, on set and offset potentials of the corona discharge may differ considerably. Probablefeatures of thecorona discharges in some other gases are discussed qualitativel

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230310

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY

摘要:

AbstractHalf integer (3/2ω0, 1/2ω0) harmonics generation under oblique incidence of the pump‐wave on the spatially inhomogeneous plasma is theoretically investigated. Harmonics generation is connected with the two‐plasmon convective instability excitation near the quarter‐critical density. Harmonics spectra and intensities depend essentially on the pump wave polarization. In particular, significant harmonics spectra broadening arises under thep‐polarized

ISSN:0005-8025    

DOI:10.1002/ctpp.19830230311

出版商:WILEY‐VCH Verlag    

年代:1983

数据来源: WILEY