The role of filamentary current distributions in the evolution of plasma-focus discharges is discussed. The force-free structures affect the energy balance during the acceleration of the plasma sheath. As a consequence, saturation of the neutron yield for high values of the energy stored in the capacitor bank occurs.

The effect of pressure anisotropy on DRAKON equilibrium is investigated. The angle of neutral beam injection effects flux surface distortions. This can explain the increase or decrease in the equilibrium beta limit.

Nonlinear propagation of ion-acoustic waves and low-frequency electrostatic modes in a dusty plasma is investigated. The evolution equations of these modes are developed and solved analytically. It is found that for small grain charge usual ion-acoustic solitons may exist in a dusty plasma, but increasing grain charge destroys them and finally they may disappear. The low-frequency electrostatic mode may be localized, forming solitons, which may act as centres of wave scattering in a dusty plasma.

Short-wave (wavelengths smaller than the ion gyroradius) low-frequency (frequencies not exceeding the ion gyrofrequency) electromagnetic equilibrium spectra are found in a current-carrying plasma. Owing to cross-field correlations, the mean values of the integrals of motion increase, whereas their cascade rates are inhibited.

A time-dependent quasi-one-dimensional model is developed for studying high- pressure discharges in ablative capillaries used, for example, as plasma sources in electrothermal launchers. The main features of the model are (i) consideration of ablation effects in each of the continuity, momentum and energy equations; (ii) use of a non-ideal equation of state; and (iii) consideration of space- and time-dependent ionization.

Ion-acoustic surface waves in a highly collisional plasma are considered. It is shown that the dispersion and damping of these waves differ considerably from those for a weakly collisional plasma.

We have studied the possibility of exciting a wake field in an electron–positron plasma by the injection of relativistic electron bunches. We have investigated the change in frequency of electronmagnetic radiation propagating through the resulting inhomogeneity. Our main conclusion is that it is not necessary to invoke a magnetic field in order to excite a wake field in an electron–positron plasma. As shown here, the necessary charge separation could come from the injection of energetic particle bunches. This mechanism of wake-field creation and subsequent particle/photon acceleration could operate in a pulsar magnetosphere, where particle bunches are extracted energetically from the pulsar surface. For example, pulsar radio emissions exhibit ultra-short intensity variations within individual pulses with time scales ranging from 1 μs to 1 ms (Cordes 1979). Several authors have proposed (Chian & Kennel 1983; Mofiz, De Angelis & Forlani 1985; Mikhailovskii, Onishchenko & Tatarinov 1985) that these pulsations can be explained as being due to soliton formation in the pulsar magnetosphere.

We believe that these micropulsations can also be explained by modulation of the radiation caused by the wake field. In order to have a quantitative estimation, we need to take into account the effects of thermal motion of particles as well as plasma inhomogeneity, etc. The present results should also be useful for understanding nonolinear photon motion in cosmic plasmas, such as those found in the early universe and in active galactic nuclei (Tajima & Taniuti 1990).

We use the general Fokker–Planck coefficients derived in the first paper of this series, which describe the interaction of energetic charged particles with weak plasma turbulence in a magnetized plasma, to calculate the mean free path λ of cosmic-ray particles along the uniform background magnetic field. This quantity is a key parameter for confining energetic charged particles in cosmic plasmas, and can be experimentally inferred from interplanetary in-situ observations of solar particle events

This study treats the system of Vlasov and Maxwell equations for the Fourier transform in space and time of a plasma referred to Cartesian co-ordinates with the z co-ordinate parallel to the uniform equilibrium magnetic field; the equilibrium plasma density depends on ηχ, where η is a parameter, and goes to zero as │χ│ → ∞. The component ky of the wave vector is taken to be zero, whereas kz is non-zero, thereby allowing for Landau damping. Coupling of the components of the electric field parallel and perpendicular to the equilibrium magnetic field (the ordinary and extraordinary waves in a homogeneous plasma) is neglected.

Cross–field transport coefficients for the electric current and heat flux have been calculated for an equal–mass plasma for various values of the Hall parameter Ωr in the range Ωr ≥ 1. Coefficients have also been calculated for parallel transport. These have been obtained using the linearized Fokker–Planck equations for both particle species, taking advantage of the mass symmetry, which leads to remarkable cancellations in the collision terms.

The expansion of a quantum electron gas (non-relativistic, no spin) is investigated via the one-particle Schrödinger–Poisson model. Classically, the nonlinear term enhances the formation of a very regular asymptotic state. By means of rescaling methods, we conjecture that the quantum asymptotic solution is identical to the classical one. Subsequent numerical simulations confirm the above conjecture and define precisely the way in which the classical limit is approached.

This paper presents the theory of an inhomogeneous source of cyclotron emission from a three-branch mode-conversion layer in a non-uniformly magnetized plasma. The physical formulation of the problem is based on the generalized Kirchhoff's law that relates, branch by branch, the emission to the absorption. General integral expressions for both absorbed and emitted energy fractions along each wave branch are obtained. A discrete multi-point model of absorbers and emitters is analysed. A variational principle for the integral of the emitted power is formulated.