On the basis of kinetic fluctuation theory, the relaxation process between the electron and ion temperatures in a magnetized inhomogeneous plasma is considered when an external pump wave parametrically decays into lower-hybrid and electron drift waves. In the region above the instability threshold, the inverse relaxation time is calculated, and its dependence on the density gradient and the pump-wave intensity and frequency is obtained. It is shown that the presence of the parametric instability leads to a decrease of the relaxation time.

It is shown that the asymptotic evolution of finite-amplitude magnetosonic waves propagating obliquely to an external uniform magnetic field in a warm homogeneous plasma is governed by a Kadomtsev–Petviashvili equation having an extra dispersive term. The dispersion is provided by finite-Larmor-radius (FLR) effects in the momentum equation and by the Hall-current and electron-pressure corrections in the generalized Ohm's law. A double-layer-type solution of the equation is obtained, and the equation is shown to reduce to a KdV–Burgers equation under certain assumptions.

This paper concerns experiments on the turbulence of a toroidal magnetoplasma in the presence of a radial electric field. The possibility of reduction of turbulence through the application of an external biasing potential has been evaluated by measuring the electrostatic fluctuations and main plasma parameters.

The theory of resonant nonlinear magnetohydrodynamic (MHD) waves in dissipative steady plasmas developed by Ballai and Erdélyi is used to study the effect of steady flows on nonlinear resonant heating of MHD waves in (a) linear, (b) weakly and (c) strongly nonlinear approximations. Nonlinear connection formulae for slow MHD waves are derived. This nonlinear theory of driven MHD waves is then used to study the interaction of sound waves with one-dimensional isotropic steady plasmas. We find that a steady equilibrium flow can significantly influence the efficiency of resonant absorption in the considered limits. In the case of strong nonlinearity, the efficiency of the resonant coupling is found to be proportional to the counterpart obtained in linear theory. The factor of proportion is approximately of the order of unity, justifying the commonly applied linear approximations.

A general form of the one-dimensional nonlinear Schrödinger equation is derived; the coefficients depend mainly on the linear dispersion relation, as does the nonlinear term. Envelope solitons may only exist together with some plasma instabilities. An example of solar radio bursts is selected as evidence for envelope solitons in the electromagnetic waveband.

An approximate analytical expression is obtained for the orbits of a charged particle moving in a cusp magnetic field. The particle orbits pass close to or through a region of zero magnetic field before being reflected in regions where the magnetic field is strong. Comparison with numerically evaluated orbits shows that the analytical formula is surprisingly good and captures all the main features of the particle motion. A map describing the long-time behaviour of such orbits is obtained.

A Monte Carlo method is used to simulate ion transport in a radiofrequency parallel-plate glow discharge with a negative-voltage pulse connected to the electrode. The dust generated during the discharge and a self-consistent electric field are taken into account. Charge exchange and elastic collisions between ions and neutral atoms and the collection and Coulomb scattering of ions on the dust particles are examined during the motion of ions in the sheath. It is found that self-consistent field, neutral gas pressure, and dust charge, dust concentration and dust size influence, to varying degrees, the energy distribution and density of ions arriving at the target, and in particular, the dust charge and concentration have significant influences. As they increase, the number of ions arriving at the target is greatly reduced. In summary, although the dust content is very low (of order 10−3) in most plasma processing devices, its influence cannot be neglected, because of the large dust size and charge (in particular, the former). Therefore, in order to produce good results with ion implantation, coating, stripping, and etching, it is necessary to reduce the dust content and control the size of dust particles.

Plasma properties during and immediately after electrical breakdown in a high-pressure gas are investigated. A simple scaling law of electrical discharge at high pressure is obtained. Introducing the normalized net ionization rate ξ, the electron temperature at breakdown is described uniquely in terms of the ionization properties of the gas, the second ionization coefficient γ at the cathode, and the parameter pd, where p is the gas pressure and d is the system dimension. The electron attachment process plays a decisive role in the breakdown phenomenon for a high-pressure gas, whereas it is not important in low-pressure discharges. An analytical expression for the high-pressure plasma density is obtained by making use of the electron rate equation. A simple analytical expression for plasma generation in a high-pressure gas provides important scaling laws in the d.c. electrical discharge system, where the electron attachment process is negligible. It is found that the logarithm of the electron density at breakdown is proportional to the discharge time τb, and is inversely proportional to the pulse risetime and the gap distance d between the two electrodes. The plasma density at breakdown is also an increasing function of the gas ionization energy εi.

It is shown that using Padé approximants in the evaluation of the plasma dispersion function Z for a Maxwellian plasma is equivalent to the exact treatment for a plasma described by a ‘simple-pole distribution’, i.e. a distribution function that is a sum of simple poles in the complex velocity plane (v plane). In general, such a distribution function will have several zeros on the real v axis, and negative values in some ranges of v. This is shown to be true for the Padé approximant of Z commonly used in numerical packages such as WHAMP. The realization that an approximation of Z is equivalent to an approximation of f(v) leads the way to the study of more general distribution functions, and we compare the distribution corresponding to the Padé approximant used in WHAMP with a strictly positive and monotonically decreasing approximation of a Maxwellian.

Higher-order nonlinear and dispersive effects on ion-acoustic solitons in a plasma consisting of two types of cold positive ions and two-temperature non-isothermal electrons are studied using a reductive perturbation method. An integrated form of the basic sets of fluid equations consisting of two types of positive ions and two types of non-isothermal electrons is derived in terms of a pseudo-potential. A perturbation solution of this equation is obtained by the Bogoliubov–Mitropolsky method. At the lowest order, we obtain a modified Korteweg–de Vries solitary-wave solution, which has a sech4 profile. Calculations are carried out at the next two higher orders. The secularity-removing condition at each order gives a correction to the velocity of the solitary wave at the corresponding order. The variations of Mach number and width of the ion-acoustic soliton with amplitude at each order are shown graphically for plasmas with H+ and He+ or with He+ and Ar+ ions, with two-temperature non-isothermal electrons.