It is shown that purely growing magnetic fields in a two-component dusty plasma can e generated due to the equilibrium drift of positive and negative dust grains. For this purpose, a linear dispersion relation has been derived by using the hydrodynamic equations for the charged dust fluids, the Maxwell equation and Faraday' law. The dispersion relation admits a purely growing instability, the growth rate of which is proportional to the equilibrium streaming speeds of positive and negative dust grains. A possible physical explanation for the instability is offered. Applications of our investigation to magnetic fields in the thin Martian environments, interplanetary spaces and dense molecular clouds are mentioned.

An improvement of an existing three-dimensional analytical model describing the solar wind flow near a reconnection site at the dayside magnetopause is reported. Introducing an arbitrary orientation of the reconnection line, general solutions for the plasma velocity and magnetic field during the transition of the magnetopause are presented, together with the development of the magnetopause transition layer away from the reconnection site.

We consider a kinetic modulational instability of broadband (random phase) magnetic-field-aligned circularly polarized dispersive Alfvén waves in plasmas. By treating random phase Alfvén waves as quasi-particles, we consider their nonlinear interactions with ion quasi-modes within the framework of the wave-kinetic and Vlasov descriptions. A nonlinear dispersion relation governing such interactions is derived and analyzed. An explicit expression for the kinetic modulational instability growth rate is presented. Our results can be of relevance to the nonlinear propagation of incoherent Alfvén waves, which have been frequently observed in interstellar media, in the solar corona and in the solar wind, as well as in the foreshock regions of planetary bow-shocks and laboratory plasmas.

A model that counts for temperature gradients in the target plasma, which leads to higher ion acoustic noise and enhanced levels of stimulated Brillouin scattering (SBS) gain and SBS reflectivity, has been adopted. Enhanced Brillouin gain leading to higher SBS reflectivity levels has been computed for non-homogeneous, non-Maxwellian plasmas. SBS reflectivity levels obtained are higher than those predicted by linear convective gain theory by several orders of magnitude and coincide with the high values of experimental data known in literature, which could not be interpreted by the linear convective gain theory.

A dipole-like rotating magnetic field was produced by a pair of circular, orthogonal coils inside a metal vacuum chamber. When these coils were immersed in plasma, large currents were driven outside the coils: the currents in the plasma were generated and sustained by the rotating magnetic dipole (RMD) field. The peak RMD-driven current was at roughly two RMD coil radii, and this current (60 kA m−) was sufficient to reverse the ambient magnetic field (33 G). Plasma density, electron temperature, magnetic field and current probes indicated that plasma formed inside the coils, then expanded outward until the plasma reached equilibrium. This equilibrium configuration was adequately described by single-fluid magnetohydrodynamic equilibrium, wherein the cross product of the driven current and magnetic filed was approximately equal to the pressure gradient. The ratio of plasma pressure to magnetic field pressure, β, was locally greater than unity.

The structure of a stationary electrostatic plasma wave propagating at a right angle to a weak magnetic field is studied. It is shown that the periodic finite amplitude wave is close in its physical structure to Bernstein–Greene–Kruskal wave of a perfectly definite type. The distinguishing feature of such a nonlinear wave is the absence of the resonant particles trapped by the wave. The electron distribution function, density perturbation and the shape of the wave electrostatic potential are found. The nonlinear dispersion relation is derived to determine the frequency shift due to the perturbation of the distribution function in the resonant region.

We investigate the instability of obliquely propagating dust waves in a collisional, magnetized plasma containing negatively charged dust grains. It is assumed that the magnetic field strength is such that the ions and electrons are magnetized, while the dust is unmagnetized. We consider both modified two-stream and dust-acoustic instabilities that are driven by an ion cross-field drift and that occur for waves propagating obliquely to the magnetic field. We use parameters that may be representative of possible laboratory experimental conditions to illustrate the growth rates. We also compare our results with prior theoretical studies of a Hall current instability of perpendicularly propagating electrostatic waves. It is found that these obliquely propagating wave instabilities may also be important for representative laboratory parameters when the cross-field drift speed is a significant fraction of the ion thermal speed.

In recent years, much attention has been devoted to the electron-temperature-gradient (ETG) driven instability as a possible explanation for the high electron thermal conductivity found in most tokamaks. The present contribution assesses whether a specific three-dimensional fluid ETG model can reproduce the conductivity observed in the Tore Supra tokamak [Equipe Tore Supra (presented by R. Aymar) 1989 Plasma Physics and Controlled Nuclear Fusion Research (Proc. 12th Int. Conf., Nice, 1988, Vol. 1.) Vienna: IAEA, p. 9]. Although the model reproduces fairly well the observed critical gradient, a large discrepancy factor, of the order of 50, is found for the ratio between the experimental and the simulated conductivity. On the basis of this study, one must conclude that the electron heat transport cannot be explained only with a fluid ETG turbulence model.

The components of the dielectric tensor for the distribution function given by Leubner and Schupfer have been obtained. The effect of the loss-cone index appearing in the particle distribution function in a hot magnetized plasma has been studied. A case study has been performed to calculate temporal growth rates of Bernstein waves using the distribution function given by Summers and Thorne and Leubner and Schupfer. The effect of the loss-cone index on growth rates is found to be quite different for the two distribution functions.

Weakly nonlinear waves in strongly magnetized plasma with slightly non-isothermal electrons are governed by a modified Zakharov–Kuznetsov (ZK) equation, containing both quadratic and half-order nonlinear terms, which we refer to as the Schamel–Korteweg–de Vries–Zakharov–Kuznetsov (SKdVZK) equation. We present a method to obtain an approximation for the growth rate, γ, of sinusoidal perpendicular perturbations of wavenumber, k, to SKdVZK solitary waves over the entire range of instability. Unlike for (modified) ZK equations with one nonlinear term, in this method there is no analytical expression for kc, the cut-off wavenumber (at which the growth rate is zero) or its corresponding eigenfunction. We therefore obtain approximate expressions for these using an expansion parameter, a, related to the ratio of the nonlinear terms. The expressions are then used to find γ for k near kc as a function of a. The approximant derived from combining these analytical results with the ones for small k agrees very well with the values of γ obtained numerically. It is found that both kc and the maximum growth rate decrease as the electron distribution becomes progressively less peaked than the Maxwellian. We also present new algebraic and rarefactive solitary wave solutions to the equation.

A time-resolved diagnostic technique was used to investigate the emission spectra from the plasmas produced by 1.06 μm, 10 ns pulsed laser ablation of semiconductor GaAs. The characteristics of the species in plasma produced at different ambient pressure were analyzed. The full width at half maximum of the spectral line was measured and analyzed according to obtained spectra of the excited atoms; several line broadening factors were estimated according to our experimental conditions and the results indicate that the Stark broadening is the main broadening mechanism. Under the assumption of local thermodynamic equilibrium, the time evolution of electron number density was deduced from the Stark broadening measurements.

The efficiency of the Alfvén impulse excitation in the auroral zone of the terrestrial magnetosphere upon the onset of the anomalous field-aligned resistance has been estimated. The impulsive disturbance excited during the onset of anomalous field-aligned resistance and electric field may signify the transition of a global magnetospheric instability into the explosive phase with positive feedback. We consider the self-consistent problem on excitation of anomalous resistance at the front of field-aligned current and reverse influence upon it from the induced currents. The analytical solution of the self-consistent problem has shown that during the entrance of field-aligned current front into the anomalous resistivity layer (ARL) an Alfvénic impulse is generated. The interaction of the external current with ARL results in the delay of the current growth. The impulse duration and delay time depend on the ratio between the Alfvén damping scale and external current width. The solution obtained indicates the possibility of using the Alfvénic impulse as an indicator of distant occurrence of anomalous resistance.

A system of nonlinear equations governing the transmission of uni-axial waves in a cold collisionless plasma subject to a transverse magnetic field is reduced to the recently proposed resonant nonlinear Schrödinger (RNLS) equation. This integrable variant of the standard nonlinear Schrödinger equation admits novel nonlinear superposition principles associated with Bäcklund–Darboux transformations. These are used here, in particular, to construct analytic descriptions of the interaction of solitonic magnetoacoustic waves propagating through the plasma.

The solution of the steady state of accretion disks surrounding non-rotating black holes is solved by numerical simulations, where we adopt a promising viscosity prescription (i.e. anomalous magnetic viscosity). We can describe the disk more exactly than other studies, because the viscosity we adopted is close to the truth accretion disk. In contrast to previous studies, the curve of the Mach number behaves differently owing to the decline of the local sound velocity with increasing radii.

The stability of these disks has been examined. We find that the O-mode (out-mode) is always unstable and its growth rate decreases monotonically with increasing wavelength, in the inner disk and in the outer disk. The I-mode (in-mode) is unstable in the outer disk, but stable in the inner disk when the wavelength is greater than a special value.