A method has been developed for the derivation of Chew–Goldberger–Low (CGL) theory for a collisionless plasma in the presence of a strong magnetic field. The pressure tensor in the pressure tensor equation is expanded in the inverse power of Larmor frequency. In the zeroth order, CGL equations are obtained and, the higher order, finite Larmor radius corrections to CGL equations are derived.

The quasi-linear equations describing the resonant evolution of a weakly inhomogeneous plasma slab under the action of Bernstein modes resulting from linear conversion of an externally injected extraordinary wave are obtained, together with a tractable form of the pertinent dispersion relation. The coefficients of electron diffusion in velocity space are computed, and their effect is compared to the effect of Coulomb collisions.

This paper describes the space-charge double-layer that forms between two plasmas with different densities and thermal energies. Three progressively more realistic models are treated by fluid theory, taking into account four species of particles: electrons and ions reflected by the double-layer, and electrons and ions transmitted through it. First, the two plasmas are assumed to be cold, and the self-consistent potential, electric field and space-charge distributions within the double-layer are determined. Second, the effects of thermal velocities are taken into account for the reflected particles, and the modifications to the cold plasma solutions are established. Third, the further modifications due to thermal velocities of the transmitted particles are examined. The applicability of a one-dimensional fluid description, rather than plasma kinetic theory, is discussed. One valuable product of this description is the potential difference across the double- layer in terms of the parameters of the two plasmas which it separates. A useful length parameter is defined characterizing the distance over which most of this potential is dropped. Comparisons are then made between theoretical predictions, and double-layer potentials and lengths deduced from laboratory and space plasma experiments.

A study is presented for electrostatic waves propagating at large angles with respect to the background magnetic field in collisional, fully ionized plasmas carrying a field-aligned current. In addition to a mode at the usual lower-hybrid frequency, it is found that the presence of electron drift velocity introduces two more modes of oscillation at several times the lower-hybrid frequency. Under appropriate conditions, a resistive instabifity, with frequency very close to the lower-hybrid frequency and growth rate proportional to the electron–ion collisional frequency, can occur. A necessary condition is that the parallel phase velocity of the wave be smaller than the electron drift velocity. A numerical example is given to illustrate the essential features of the instability.

The definition of the ‘combined field’ and the ‘combined field potentials’ allows one to formulate a constrained minimum energy problem. The constraints can be put in a relativistically covariant form. The equations of stable equilibrium, for a non-rotating charged fluid, are obtained. If the physical conditions are suitably chosen, a special kind of Alfvén-like velocity may exist.

Herein is described a calculation of the effective coffision frequency νeff of a low- density, shock-heated argon plasma under the influence of a weak electric field which oscillates harmonically with angular frequency ω. It is shown that, for the high frequency case ω > where is the collision frequency in a Maxwellian gas plasma, one has νeff ⋍ 2, provided that the imaginary part of the argon plasma conductivity is negligibly small in comparison to the real part. The influence of the theoretical model used to calculate νeff on the values of the electron temperature Te derived from measurements is compared with the results obtained in a data reduction for which the hard-sphere model for particle encounters was utilized.

A statistical theory of one- and two-dimensional temperature anisotropy driven Weibel instabilities is proposed. The theory is based on a two-temperature canonical distribution and the mean field approximation. It applies to a nonlinear, periodic, charge-neutralized, and collisionless system. Using a partition function formalism, equations of state are derived which predict upper bounds on the magnetic field energy produced by a quasi-static evolution of these instabilities. Theoretical predictions are in good agreement with results from numerical simulations.

The relativistic Vlasov equation together with Maxwell's equations are used in a study of p-polarized electromagnetic waves incident on a warm plasma halfspace. The domain for dual propagation of longitudinal and transverse waves is derived as a function of density, temperature and incident angle at a given frequency. Expressions for the reflection and absorption coefficients are obtained in the non-relativistic limit. It is found that maximum absorption occurs at an angle dependent on the density and temperature of the plasma, above which dual propagation will not occur. It is inferred that the density–temperature space available for dual propagation diminishes with the growth of the maximum angle for such propagation.

In the present analysis, a normal mode approach is used to study waves in a plasma subjected to a spatially uniform but temporally stochastic magnetic field. The first part deals with the evolution of circularly polarized transverse waves. Making a linear analysis, it is shown that the coherent waves are damped. The nature of the damping is determined by the Kubo number. In the second part, the nonlinear interaction of three coherent waves propagating along the magnetic field is analyzed. The coupling coefficients for the interaction of two circularly polarized waves and a longitudinal one are calculated. It is shown that for coherent waves, the system is equivalent to the interaction of two damped transverse modes with an undamped longitudinal one.

Plane wave propagation in temperate plasmas consisting of n ion species is calculated analytically for collisionless plasmas of arbitrary composition. Numerical results are given for the complex refractive index of plasmas including collisions between particles of any kind and at arbitrary angles of propagation. There are two waves propagating at all angles other than 90°, one wave showing resonances at each of the n cyclotron frequencies of the ions involved. High ion-ion collision frequencies combine the motions of the ions to give new mass and composition weighted hybrid ion cyclotron resonances. At right angles to the external magnetic field one wave will propagate in the ion cyclotron range showing n – 1 ion-ion hybrid resonances and n – 1 hybrid cut-offs. The ion-ion hybrid resonances can be traced down to propagation at angles smaller than 90°, disappearing for parallel propagation. The hybrid resonance frequencies are close to the cyclotron frequencies of the ions with small relative concentrations. Damping of the waves in the neighbourhood of the ion-ion hybrid resonances is strongly affected by ion-ion collisions.

Nonlinear propagation of an electron-acoustic wave in a magnetoplasma is considered. Accounting for the exact electron and ion nonlinearities, we show that the equations governing the dynamics of these waves can be written in terms of the energy integral of a classical particle. A careful analysis of the potential reveals the existence of exact planar solitary waves. Application of our investigation to space plasmas is pointed out.

Profile modification in the underdense region of laser-plasmas with spatially uniform temperature Te, is studied. A multiple scale method is used to describe self-consistently the plasma flow and the wave field, in (i) the scale of the field wavelength, and (ii) the overall expansion scale. For Te∝ taordinary differential equations with definite boundary conditions are obtained. For a = 0 and weak fields, we explicitly solve the equations and relate the field in the critical layer to the incident field.

The validity of hydrodynamic approximations for non-equilibrium plasmas is examined, with emphasis on applications to laser-driven fusion pellets. Typical density–temperature trajectories of such pellets, as predicted by hydrodynamic calculations in the published literature, are shown to lie sometimes outside the region of validity of hydrodynamic theory, which is an unsatisfactory situation. In view of this, we discuss certain criteria which can be easily used to test the self- consistent validity of any hydrodynamic result. Finally, it is noted that in the low-density, low-temperature plasma region, hydrodynamics initially breaks down because of a breakdown in conventional microscopic linear response theory. A modified microscopic theory is proposed which continues to be valid in this region. This may correspondingly extend the validity of hydrodynamics to plasmas of somewhat lower temperatures and densities.