摘要:

The excitation of plasma waves is reviewed, organized according to the mode of excitation: linear wave coupling, use of exciters (such as antennas and probes), particle‐velocity anomalies (such as streams and loss cones) and wave‐wave stimulation (such as three‐wave and ec

ISSN:0048-6604    

DOI:10.1029/RS007i008p00833

年代:1972

数据来源: WILEY

摘要:

Three short papers were read after the review paper by T. W. Johnston.P. E. Vandenplas(Ecole Royale Militaire, Brussels, Belgium) gave a survey concerning resonances observed in laboratory plasma capacitors. For such a capacitor with plate distanceland plates covered with rarified sheaths, cold plasma theory gives the main resonance of an infinite plane capacitor as a serial one at a frequency ƒN(1 −a/l)1/2, whereais the thickness of the (homogeneous) plasma sheath between the plates. In warm plasma theory apart from a correction term of the order λDe2/a2(λDeis electron Debye‐length) this resonance splits up into a narrow series of successive resonances, the distance of which is controlled by the same parameter. Furthermore, since the ‘warm’ dispersion equation is of fourth order now, other eigenvalues lead to new resonances of another type, which have been found in the labor

ISSN:0048-6604    

DOI:10.1029/RS007i008p00843

年代:1972

数据来源: WILEY

摘要:

A survey of wave‐coupling phenomena is given. Different physical influences are discussed from a rather general plasma‐wave equation displaying these influences. Nonlinear interaction is considered and some basic examples are given. Attention is called to certain physical points of view related to nonlinear analy

ISSN:0048-6604    

DOI:10.1029/RS007i008p00845

年代:1972

数据来源: WILEY

摘要:

W. R. Larenz'review paper (printed in this issue) presented a systematic categorization of various linear and nonlinear coupling mechanisms encountered in the hydrodynamically approximated warm plasma. As on several occasions during this symposium, the range of validity of the fluid model was questioned; the discussion provided the usual answers of the adequacy of the model as long as the wave numbers of electron or ion waves involved in plasma processes are well below the Debye wave numberkD. The utility of the fluid model, when adequate, was emphasized in connection with radiation and boundary value problems since the complexities introduced by kinetic theory tend to render much of the required analysis intractable. For better understanding of the influence of anisotropy, it was pointed out that substantial anisotropy in the particle velocity distribution may be accommodated by an anisotropic pressure tensor within the hydrodynamic description.

ISSN:0048-6604    

DOI:10.1029/RS007i008p00853

年代:1972

数据来源: WILEY

摘要:

The instability of plane‐parallel plasma streams with a nonuniform velocity profile, both in the absence and in the presence of a longitudinal magnetic field, has been investigated. The results for plasma streams are compared with those of ideal conductive liquid flows. Although for instability in a plane‐parallel ideal‐liquid flow the theorem ofRayleigh[1880] is valid, it is not so for plasma st

ISSN:0048-6604    

DOI:10.1029/RS007i008p00857

年代:1972

数据来源: WILEY

摘要:

Among the variety of problems arising from attenuating influences on the propagation of waves, three will be reviewed: (a) determination of the correct gas‐kinetic description of collisions between the plasma particles and their relation to the conductivity tensor and the dispersion equation, (b) the generalization of the basic laws of geometric optics for moderate collisional absorption, and (c) the calculation of wave‐mode attenuation arising from linear‐mode coupling in a full‐wave theory for a cold, stratified, magnetized absorbing

ISSN:0048-6604    

DOI:10.1029/RS007i008p00871

年代:1972

数据来源: WILEY

摘要:

The last session with invited papers and contributions dealt with two topics: (a) attenuation and (b) two‐stream instability. It also gave an occasion to include a few other contributions, which could not be presented during the preceding sessions.K. Suchypresented an invited paper on topic a dealing with collisional damping for linear wave coupling. Questions concerned with the physical meaning of this coupling mechanism and with some difficulties concerning the notations for describing the polarization of waves in a magnetoplasma have been answered in the printed version of this paper which is found in this issu

ISSN:0048-6604    

DOI:10.1029/RS007i008p00885

年代:1972

数据来源: WILEY

摘要:

Some remaining contributions were read in a first part of this session.R. F. Benson(Goddard Space Flight Center, GSFC, Greenbelt, Md., USA) read two papers concerned with resonances observed in topside sounders. The first paper considered the small frequency shifts which are found for successive harmonics of the electron gyro frequency, ƒB. When the magnetic field is computed from observed frequencies, there is agreement with the result of the well‐known computer programs (using Legendre development) for the sixth‐order reson

ISSN:0048-6604    

DOI:10.1029/RS007i008p00887

年代:1972

数据来源: WILEY