摘要:

AbstractThe excitation of symmetric and antisymmetric plasma waves by a beam layer that moves within a homogeneous plasma enclosed by a metallic wall was dealt with theoretically. Investigations were carried out for the magnetic field free case and for a magnetized electron beam. In the latter case, the beam electrons are assumed to be unable to move in the perpendicular direction. The theoretical model bases upon an extension of the well known single wave theory to a two‐dimensional beam‐plasma system. Special emphasis should be paid to the fact that the perpendicular wave profile of the excited waves was determined self‐consistently. Energy and momentum balance equations are derived for this system. The theoretical method outlined in this paper which is based on a Green's‐function technique can be extended easily to three‐dimensional systems or to beam‐plasma systems with other boundary conditions. The main features of the saturation process of the basic unstable wave types are discussed. Several interesting effects were found in the magnetic field free case: (i) numerical solutions describe an increasing steepening of the wave amplitudes in perpendicular direction near the center of the system for the symmetric potential wave; (ii) for the antisymmetric wave, a smoothing tendency was found in the development of the perpendicular wave potential profile; (iii) spatial separation of the slow and fast beam electrons was observed; (iv) it is shown for the antisymmetric potential wave type that, under certain conditions, a very efficient beam particle retardation mechanism occurs which is connected with a strong reduction of the formation of a fast particle group; (v) generally it was shown that the conversion of the kinetic energy of the beam electrons into the plasma wave energy may be more effective as compared with the case of the magn

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270202

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractWe discuss surface waves propagating on a semi‐infinite cold plasma with slowly varying density. Previous results are modifie

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270203

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractAnalytical study of the stimulated Brillouin scattering in a two‐ion species plasma has been done using the hydrodynamical model. When strong nonlinear effect becomes significant i.e., when the quiver velocity of the electron becomes of the order of or greater than its thermal velocity, the damping becomes intensity dependent which modifies the results over the weak nonlinearity. In this regime the plasma behaves as a collisionless medium. The inclusion of the second species of the ions modifies the instability and decreases the growth rate. Its application in fusion plasma has been discusse

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270204

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractConvective Cell formation due to nonlinear interaction of interchange mode is studied using multiple time and space scales. Basic interchange mode equation is modified to obtain nonlinear localized structure with modulational perturbation in the drift direction and periodic boundary condition for the perturbation in the direction of the density gradient. To study modulational instability we have deduced nonlinear evolution equation for the first order perturbation from third order secularity elimination condition. Modulational instability, which is responsible for localized structure, is studied in two limits of the dispersion relation.

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270205

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe instability in a stratified layer of a self‐gravitating partially ionized plasma has been studied in the presence of effects of Hall currents. For a plasma permeated by a uniform vertical magnetic field, the dispersion relation has been obtained through variational method. It is found that the Hall currents have a destabilizing effect while the neutral gas frictional effects have a stabilizing influenc

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270206

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractThe perturbing ion motion effect on the relative central dip of the Hβ(Dβ) has been firmly established for numerous values of the reduced mass of the radiating atom – perturbing ion. In this paper the ion motion effect is confirmed for the cases in which the reduced mass and electron densities are constant, while the temperature of plasma is changing. Also a dependence of the dip values on electron densityNeis checked following theoretical results of Demura, Lisitza and Sholin. It is shown that the dip value is a linear function ofN e−α, where α is a number c

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270207

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

摘要:

AbstractAn investigation is given for the effects of smoothing on the Abel inversion method for obtaining radial intensity profiles from chordal intensity profiles. Before the radial intensities are calculated by means of the familiar inversion methods, such as by Nestor‐Olsen, Bockasten, Frie, etc., the chordal intensities with random scatterings are smoothed by easily available methods, the least‐square fitting with Taylor expansion correction and theB‐spline fitting. Through numerical simulation tests, it is shown that this procedure of smoothing is very useful for an accurate Abel inversion without relying upon more complicated inversion methods having clever smoothing processes, e.g., by Piessens, Fleurier and Chapelle, Glasser et al.

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270208

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY

ISSN:0005-8025    

DOI:10.1002/ctpp.19870270201

出版商:WILEY‐VCH Verlag    

年代:1987

数据来源: WILEY