It is shown that the interaction of dust with neutral plasma particles can lead to attractive forces between dust particles, both in the case where the distance between dust particles is less than the mean free path of neutral particles and in the case where it is greater. The expressions for attractive forces differs in the two limits only by a numerical coefficient. The additional force of dust interaction is found to be due to the neutrals created by recombination of charged plasma particles on the surface of dust particles. The influence of radiative dust cooling on dust–dust interaction is considered.

A numerical investigation of wave propagation in a magnetized plasma layer is performed. Four families of waves can propagate: plasma, cyclotron, anisotropic and waveguide modes. It is shown that the singular waves propagate at the crossing points of the waves with the complex zone boundary. The influence of the interface, the layer width and the magnetization of the plasma on the spectrum of the waves is analysed.

A numerical investigation of anisotropic waves propagating in a magnetized plasma layer is performed. In gyrotropic plasma layers, there are two regions in which electromagnetic waves exist owing to the anisotropic properties of the plasma. Mainly these are Rayleigh pseudosurface waves. In the upper anisotropic region, a wave exists only in a planar waveguide. In the lower anisotropic region, there are two waves. The dispersion and the origin of these waves are analysed. The distribution of the energy and the Poynting vector are unique, and they differ from those of other families of electromagnetic waves. At small wavenumbers, the energy is concentrated in one of the dielectrics and at large wavenumbers, it is concentrated in the plasma.

A hydrodynamic approach is employed to study a cosmic-ray–plasma system, which comprises thermal plasma, cosmic rays and two oppositely propagating Alfvén waves. The hydrodynamic approach is a good approximation in dealing with the structure or dynamics of the system. In this paper, we concentrate on the steady-state structures of the system, in particular, structures with continuous (or smooth) profiles. Three mechanisms are responsible for the energy exchange between different components. They are work done by plasma flow via pressure gradients, cosmic-ray streaming instability and stochastic acceleration. The interplay between these mechanisms generates several morphologically different structures. They may be divided into two categories: one looks like the test-particle picture and the other looks like a modified shock. Very often the profiles are non-monotonic, which is in sharp contrast to systems with only thermal plasma and cosmic rays, whose flow velocity (and cosmic-ray pressure) profiles are always monotonically decreasing (and increasing).

Conditions for exciting higher-harmonic electrostatic dust cyclotron waves in a collisional dusty plasma are investigated. Linear kinetic theory is used, and the effects of neutral–charged particle collisions are taken into account. In a plasma with negatively charged dust, electrostatic dust cyclotron waves can be driven unstable by ions drifting along the magnetic field. It is found that, under certain conditions, the critical ion drift for the excitation of higher-harmonic electrostatic dust cyclotron waves (i.e., ω ∼ mΩd, where m [ges ] 2 and Ωd is the dust cyclotron frequency) can be comparable to the critical drift for the excitation of the fundamental cyclotron harmonic (i.e., ω ∼ Ωd). Stability conditions are investigated for ranges of parameters that may be relevant to laboratory dusty plasmas.

We consider the motion of charged particles in a static magnetic reversal with a shear component, which has application for the stability of current sheets, such as in the Earth's geotail and in solar flares. We examine how the topology of the phase space changes as a function of the shear component by. At zero by, the phase space may be characterized by regions of stochastic and regular orbits (KAM surfaces). Numerically, we find that as we vary by, the position of the periodic orbit at the centre of the KAM surfaces changes. We use multiple-timescale perturbation theory to predict this variation analytically. We also find that for some values of by, all the KAM surfaces are destroyed owing to a resonance effect between two timescales, making the phase space globally chaotic. By investigating the stability of the solutions in the vicinity of the fixed point, we are able to predict for what values of by this happens and when the KAM surfaces reappear.