摘要:

The second‐order pressure tensor and heat‐flux vector are obtained for a one‐component plasma by applying the Chapman‐Enskog method of solution to the Balescu‐Guernsey‐Lenard kinetic equation. To illustrate the temperatures and densities at which second‐order effects may be important in plasmas, the hydrodynamic problem of Couette flow between flat plates is analyzed.

ISSN:0031-9171    

DOI:10.1063/1.1692187

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

A quasilinear theory is formulated which includes the microscopic fluctuation fields as well as the coherent waves. The study emphasizes those cases in which the propagating mode of the fluctuation field gives rise to a dominant contribution to the particle correlation. In other words, in these cases the spontaneous Cˇerenkov emission of plasmons can play a more important role than the two‐particle collision process. The instability which is responsible for the turbulence can be of either an electrostatic, electromagnetic, or mixed nature. The effect of an external magnetic field is also considered in the present theory. The final result is valid for an arbitrary ratio of the energy density of the coherent wave to that of the fluctuation field althought the condition of weak turbulence is imposed throughout the analysis.

ISSN:0031-9171    

DOI:10.1063/1.1692188

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

Motion of charged particles in arbitrary random electric and magnetic fields is analyzed, and the statistical acceleration rate is derived in terms of power spectra of functions of the applied fields. The treatment is extended to stochastic acceleration in a magnetic mirror; upper and lower bounds (differing by a factor of 2) for the particle acceleration rate are derived for the case when the half‐power spectrum of the electric field spans the spectrum of particle gyrofrequencies in the mirror.

ISSN:0031-9171    

DOI:10.1063/1.1692189

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

The roots of the dispersion relation describing the linear interaction between a plasma and a relatively low density electron beam are investigated. The dispersion curves exhibit a nontrivial change in topology at a particular value of the appropriately scaled thermal velocity of the beam.

ISSN:0031-9171    

DOI:10.1063/1.1692190

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

The oscillations of resonant electrons in the potential of a large‐amplitude, spatially propagating plasma wave result in: (1) periodic maxima in space of wave amplitude, (2) growth of sidebands on the transmitted frequency, and (3) periodic enhancement of the energy of the trapped electrons. Measurement of these effects is reported.

ISSN:0031-9171    

DOI:10.1063/1.1692191

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

Correlation techniques are applied to low‐frequency probe signals detected in a highly ionized hollow‐cathode gas‐fed arc plasma in an axial magnetic field. One set of oscillations is found to be an ion acoustic wave propagating at an angle to the magnetic field. Drift waves are also observed.

ISSN:0031-9171    

DOI:10.1063/1.1692192

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

Dispersion relations for longitudinal and transverse waves propagated perpendicularly to an externally applied high‐frequency electric field in a fully ionized plasma has been obtained. It has been shown that in addition to&ohgr; ∼ &ohgr;0(&ohgr;0is the characteristic electron frequency), the longitudinal mode may be excited with frequencies&ohgr; ≃ &OHgr;k± &ngr;(&OHgr;k2 = c2k2 + &ohgr;02, &ngr; is the external field frequency); and under certain conditions the excitation near&ohgr;0may be unstable. For the transverse mode instabilities may occur owing to resonance between a backward and a forward moving wave of the same frequency and vice versa. Apparently these are owing to the periodic nature of the dispersion relations found and to the mode‐mode coupling present.

ISSN:0031-9171    

DOI:10.1063/1.1692193

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

Raising electron temperature in an infinite homogeneous plasma of electrons and hot ions tends toward stabilization of the absolute instabilities caused by a nonmonotonic or “loss‐cone” distribution of ion velocities perpendicular to the external magnetic field. When the ion plasma frequency exceeds the ion gyrofrequency, this stabilization is incomplete although the residual instabilities have small growth rates and large axial wave lengths, permitting some degree of control by adjusting plasma parameters.

ISSN:0031-9171    

DOI:10.1063/1.1692194

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

The nonlinear interaction of electromagnetic waves propagating in a cold plasma across a magnetic field is investigated. The amplitude of the generated wave is evaluated, and numerical computations are given for two cases of interest: (a) the interaction of an extraordinary wave with an ordinary wave leading to the generation of an ordinary wave; (b) the interaction of two ordinary waves leading to the generation of an extraordinary wave. The results show that under appropriate conditions the detection of generated wave is feasible and the scheme should provide a diagnostic method for measuring the local density and its fluctuations in magnetized plasmas.

ISSN:0031-9171    

DOI:10.1063/1.1692195

出版商:AIP    

年代:1968

数据来源: AIP

摘要:

A preliminary study is made of overstable modes due to resistivity gradients in a current‐carrying plasma slab. A restricted set of solutions satisfying a constant pressure assumption is found for the magnetohydrodynamic equations. These solutions turn out to be overstable in a certain range of the resistivity.

ISSN:0031-9171    

DOI:10.1063/1.1692196

出版商:AIP    

年代:1968

数据来源: AIP