The scattering of free drift waves by drift vortices is investigated analytically in the Born and eikonal approximations. Scattering amplitudes and scattering cross-section are found for a wide range of parameters of the vortex and wave. It is shown that under certain conditions the wave–vortex interaction becomes very strong; that is, the scattering cross-section is much more than the vortex radius.

The possibility for a drift dipole vortex to trap free drift waves is demonstrated. Drift perturbations can be trapped near the centre of the vortex or at its sides. The localization domain and eigenfrequencies of trapped modes are obtained.

The toroidal spread of laser blow-off injected lithium is studied. The temporal variation of the toroidal and radial distributions of the first two ionization stages of cross-field-injected lithium is measured around the injection location by a gated, image-intensified CCD camera. Broad atomic distribution and deep radial penetration of the injected beam is observed. The toroidal delay of the arrival of the Li+ ions is investigated by detecting the intensity of their line radiation at different toroidal positions away from the injection port. Possible explanations for the observations and the possible mechanism for the toroidal spread are discussed in detail. A comparison of the detected distribution of Li ions with a 1D simulation is presented.

The effects of dispersion of slow electromagnetic surface waves propagating across an external magnetic field in planar metallic waveguides with dielectric coating and non-uniform plasma filling on the harmonics of the electron cyclotron frequency are studied. The theoretical investigation of the surface modes is carried out using a kinetic description for the plasma particles and a mirror-reflection model for the interaction between particles and plasma boundary. The effect of the transverse plasma density inhomogeneity on the electron surface cyclotron-wave spectrum is investigated.

A theory is proposed that describes in a self-consistent manner damping and particle acceleration within cavitons. The framework of the approach makes it possible to formulate a set of self-consistent equations taking into account the change in the particle distribution function due to the interaction with cavitons and the damping of the waves within the cavitons due to the interaction with resonant particles. The spatial inhomogeneity of the distribution function of resonant particles in the vicinity of a caviton produces a new type of damping. The new damping mechanism is present for any inhomogeneity produced both by the other cavitons (or empty cavitons) in a strongly turbulent plasma or by any other source. This new type of damping is important for arresting wave collapse.

Stationary flows of an ideal plasma with translational symmetry along the (vertical) z axis are considered, and it is demonstrated how they can be described in the intrinsic (natural) coordinates (ξ, η, &), where ξ is a label of flux and stream surfaces, η is the total pressure and ϑ is the angle between the horizontal magnetic (and velocity) field and the x axis. Three scalar nonlinear equilibrium equations of mixed elliptic–hyperbolic type for ϑ(ξ, η), ξ(η, ϑ) and η(ϑ, ξ) respectively are derived. The equilibrium equation for ϑ(ξ, η) is especially useful, and has considerable advantages compared with the coupled system of algebraic–differential equations that are conventionally used for studying plasma flows. In particular, for this equation the location of the regions of ellipticity and hyperbolicity can be determined a priori. Relations between the equilibrium equation for ϑ(ξ, η) and the nonlinear hodograph equation for ξ(η, ϑ) are elucidated. Symmetry properties of the intrinsic equilibrium equations are discussed in detail and their self-similar solutions are described. In particular, magnetohydrodynamic counterparts of several classical flows of an ideal fluid (the Prandtl–Meyer flows around a corner, the spiral flows and the Ringleb flows around a plate, etc.) are found. Stationary flows described in this paper can be used for studying both astrophysical and thermonuclear plasmas.

We consider the spectrum and stability of a compressible, rigidly rotating plasma column with constant magnetic pitch. It is found that when the pressure on axis is zero, a continuous spectrum arises, which may become unstable. When the pressure on axis is finite or a conducting core is included, the spectrum is discrete, but may still be unstable. The instability is due to the poloidal magnetic field and/or the rotation of the cylinder in combination with the density profile. It is found numerically that the pressure stabilizes both types of instabilities.

This paper gives a complete kinetic theory of atomic discharges whatever their parameters. Very high-frequency discharges and high-pressure continuous discharges were studied in an earlier paper by the same authors [J. Plasma Phys. 54, 309 (1995)]; in the present paper we study low-pressure continuous discharges or high-frequency discharges whose parameters satisfy different conditions and therefore cannot be described by the earlier model. Analytical results are applied to a high-frequency argon discharge and to a low-pressure continuous argon discharge. The results are in good agreement with the numerical results of Ferreira and co-workers.

Assuming the averaged (background) electron distribution in a crossed-field device, such as a magnetron or crossed-field amplifier, to be slowly varying between the cathode and the anode, we develop a WKB approximation for the cold-fluid plasma equations of a planar magnetron. In this approximation, we can give general expressions for the solution of linearized, high-frequency oscillations in such a device in terms of two integrals. Assuming also that the high-frequency wave in the slow-wave structure drives the response in the electron plasma, we are then able to show that the current drawn by a crossed-field device will be proportional to the power propagating in the slow-wave structure. Thus the device will operate as a linear amplifier. We also show, in the same approximation, that the averaged electron sheath that forms when the device is operating is independent of the current being drawn. Thus the current will not be limited by the sheath, but only by the ability of the cathode to emit electrons. In the process, we also obtain expressions for the linear growth rate and the value of the quasilinear diffusion coefficient at the diocotron resonance, in terms of parameters of the background electron sheath.

It is shown that the recently published work of Pandey and Dwivedi [J. Plasma Phys. 55, 395 (1996)] dealing with dust-acoustic waves in a self-gravitating unmagnetized dusty plasma is erroneous. This is demonstrated on the basis of a dispersion relation in which gravitational and electrostatic forces are kept on an equal footing. Furthermore, a general linear dispersion relation for the dust-acoustic and dust-ion acoustic waves in self-gravitating dusty plasmas is obtained, taking into account the dust-charge perturbations. Specific results for limiting cases are discussed.

Electron-cyclotron maser emission is investigated in the regime where wave growth in the electrostatic Bernstein modes dominates (ωp/Ωe>1.5). A semirelativistic growth rate is derived assuming that the wave dispersion is dominated by a cool background electron distribution and the instability is driven by a low-density hot loss-cone-like electron distribution. The properties of Bernstein wave growth are most strongly dependent on the relative temperatures of the hot and cool electron distributions. For Thot/Tcool[gsim]10, the fastest growing Bernstein waves are produced at frequencies just below each cyclotron harmonic in Bernstein modes lying below the upper-hybrid frequency. For Thot/Tcool[lsim]10, additional Bernstein modes above the upper-hybrid frequency are excited, with wave frequencies in each excited mode lying significantly above the corresponding cyclotron harmonic. The dependence of Bernstein wave growth on the relative hot and cool electron number densities and emission angle is also discussed.