An earlier elaborated model of the electron, being based on a revised quantum electrodynamic theory, is further investigated in terms of an improved numerical iteration scheme. This point-charge-like model is based on the “infinity” of a divergent generating function being balanced by the “zero” of a shrinking characteristic radius. This eliminates the self-energy problem. According to the computations, the quantum conditions on spin, magnetic moment, and magnetic flux, plus the requirement of an elementary charge having the experimental value, can all be satisfied within rather narrow limits by a single scalar parameter. The revised model prevents the electron from “exploding” due to its eigencharge.

Small solid metallic objects in relative motion to thermal plasmas are studied by numerical simulations. We analyze supersonic motions, where a distinctive ion wake is formed behind obstacles. At these plasma drift velocities, ions enter the wake predominantly due to deflections by the electric field in the sheath around the obstacle. By irradiating the back side of the object by ultraviolet (UV) light, we can induce also an enhanced photo-electron population there. The resulting charge distribution gives rise to a pronounced local potential and plasma density well behind the object. This potential variation has the form of a three-dimensional ion acoustic double layer, containing also an ion phase space vortex. The analysis is supported also by one-dimensional numerical simulations to illustrate the importance of boundary conditions, Dirichlet and von Neumann conditions in particular.

The existence of large amplitude solitary waves in a plasma comprised of a cold negative dust fluid, adiabatic positive dust fluid, Boltzmann electrons and non-thermal ions is theoretically investigated. Different regions in parameter space that correspond to different values of the ratio of the charge-to-mass ratios of the positive and negative dust grains have been identified where either negative or positive potential solitary wave structures occur and a region where coexistence of negative and positive potential solitary waves is supported.

The hydrodynamic equations of positive and negative ions, Boltzmann electron density distribution and Poisson equation with stationary dust particles are used along with the reductive perturbation method to derive a three-dimensional cylindrical Kadomtsev–Petviashvili equation. The generalized expansion method, used to obtain a new class of solutions, admits a train of well-separated bell-shaped periodic pulses. At certain condition, these periodic pulses degenerate to solitary wave solutions. The effects of the physical parameters on the solitary pulses are examined. Finally, the present results should elucidate the properties of ion-acoustic solitary pulses in multi-component plasmas, particularly in Earth's ionosphere.

It is shown that pair plasmas, through the new focusing–defocusing nonlinearity generated by an ‘asymmetry’ in initial temperatures of constituent species, can support multidimensional, stable, large-amplitude light bullets as well as bullets carrying vortices, i.e. spinning bullets.

The nonlinear propagation of dust-acoustic (DA) waves in a dusty plasma consisting of Boltzmann-distributed ions, vortex-like distributed electrons and mobile charge fluctuating positive dust has been investigated by employing the reductive perturbation method. The effects of dust grain charge fluctuation and the vortex-like electron distribution are found to modify the properties of the DA solitary waves significantly. The implications of these results for some space and astrophysical dusty plasma systems are briefly mentioned.

In the far edge, in L-mode plasmas and the outer parts of the H-mode barrier, tokamak plasmas may be so collisional that parallel electron motion can be neglected or included as a perturbation. Thus we have a regime that is basically two dimensional. We will here consider the outer part of the H-mode barrier where transport is small. Recently a condensation mode was found for this regime. We have extended the theory to the nonlinear regime.

The existence of a new class of astrophysical objects, where gravity is balanced by the shielded electric fields associated with the electric charge on the dust, is shown. Further, a mass limit MA for the maximum dust mass that can be supported against gravitational collapse by these fields is obtained. If the total mass of the dust in the interstellar cloud MD > MA, the dust collapses, while if MD < MA, stable equilibrium may be achieved. Heuristic arguments are given to show that the physics of the mass limit is similar to the Chandrasekar's mass limit for compact objects and the similarity of these dust configurations with neutron and white dwarfs is pointed out. The effect of grain size distribution on the mass limit and strong correlation effects in the core of such objects is discussed. Possible location of these dust configurations inside interstellar clouds is pointed out.

A dust crystal levitated in the sheath of a radio-frequency plasma is subjected to a pulsed plasma jet expelled from a minicoaxial gun. The dust particles, initially found at rest and self-organized in a 3-D structure, are dragged by the plasma jet for a short distance and come to rest when the action of the jet terminates. The trajectories of the microparticles are tracked in vertical and horizontal planes with a high-speed camera. From in situ observations of dust particle dynamics the dust acceleration is compared to numerical simulations.

Our basic-plasma experiments relating to fusion-oriented and space plasmas have yielded deep and unique insight into wave and instability physics in ordinary electron-ion and unusual pair-particle plasmas. Here recent results on flow shears, polarization reversal and pair-ions are presented in the way that light is shed on the underlying physics.

Review of plasma processes in the Earth's environments containing nano- and microscale grains is presented. Possible observational manifestations of dusty ionospheric plasmas during high-speed meteor showers are described. A unified explanation of ionization properties of the polar mesosphere under summer conditions is given. Dusty plasma processes are also considered in application to active geophysical rocket experiments which involve release of some gaseous substance in near-Earth space, the origin of the primary Earth's crust, hydrosphere and atmosphere, and global electromagnetic Schumann resonances.

This paper describes some aspects of lower-hybrid wave activity in space plasmas. Lower-hybrid waves are particularly important since they can transfer energy efficiently between electrons and ions in a collisionless magnetized plasma. We consider the ‘fan’ or anomalous Doppler resonance instability driven by energetic electron tails and show that it is responsible for the generation of lower-hybrid waves. We also demonstrate that observations of their intensity are sufficient to drive the modulational instability.

The coupled Shukla–Varma (SV) and convective cell mode is revisited in classical and quantum dusty magnetoplasmas. It is shown that the inclusion of electron thermal effects modifies the original coupled SV and convective cell mode. It is also discussed how the quantum effects can be incorporated in the coupled SV and convective cell mode.

A set of magneto-hydrodynamic (MHD) equations that govern the nonlinear dynamics of drift-Alfvén waves with arbitrary spatial scales in comparison with the ion Larmor radius is derived. It is shown that in the linear limit a Fourier transform of these equations yields the dispersion relation which in the so-called Padé approximation corresponds to the fully kinetic theory.

The magnetized plasma-wall transition (MPWT) layer occurring, for example near a tokamak diverter, typically consists of three distinct sublayers: the Debye sheath (DS), the magnetic presheath (MPS) and the collisional presheath (CPS), with characteristic lengths λD (electron Debye length), ρi (ion gyroradius) and λ (smallest relevant ion collision length), respectively. For analytical simplicity one usually assumes the ordering λD ≪ ρi ≪ λ, or, equivalently, and (‘asymptotic three-scale (A3S) limit’), in which the three sublayers are precisely defined. In the present work the equations and length scales governing the transition, or the ‘intermediate’ regions between neighboring sublayers (DS–MPS, MPS–CPS), in the A3S limit are derived, allowing one to avoid the singularities arising from the ϵDm → 0 and ϵmc → 0 approximations. The MPS entrance and the related Bohm–Chodura condition is defined in a natural way. It is found that in the hydrodynamic Ti = 0 approximation the intermediate scales and equations have a universal form and a similar structure not only for the MPS–DS and CPS–MPS transitions but also for the DS–CPS transition in the non-magnetized case.

Star formation occurs in dark molecular regions where the number density of hydrogen nuclei nH exceeds 104 cm−3 and the fractional ionization is 10−7 or less. Dust grains with sizes ranging up to tenths of microns and perhaps down to tens of nanometers contain just less than 1% of the mass. Recombination on grains is important for the removal of gas-phase ions, which are produced by cosmic rays penetrating the dark regions. Collisions of neutrals with charged grains contribute significantly to the coupling of the magnetic field to the neutral gas. Consequently, the dynamics of the grains must be included in the magnetohydrodynamic models of large-scale collapse, the evolution of waves and the structures of shocks important in star formation.

The paper presents experimental investigation of flow of dusty plasma medium formed by macroparticles in argon plasma. The dependences of the coefficient of shear viscosity of such liquid on the external force causing the flow of dusty plasma liquid and on the pressure of plasma-generating gas are studied. It is found that the viscosity of the dusty plasma medium decreases with increasing shear stress and increases with increasing pressure of buffer gas. An experimental investigation of the dynamics of macroparticles in an unperturbed liquid dusty plasma medium as a function of coupling parameter is performed; in so doing, formations of particles whose motion is correlated are observed in the region of high values of coupling parameter. It is assumed that the non-Newtonian pattern of dusty plasma liquid may be due to the emergence of crystal-like dusty plasma clusters in the ‘liquid’ phase. An experimental investigation of a crystalline dusty plasma structure under the effect of laser radiation is performed; in so doing, a macroscopic flow of the crystalline dusty plasma structure is observed under the effect of shear stress. The mechanism of formation and subsequent annihilation of edge misfit dislocations is observed and the threshold pattern of such flow is established; the threshold value of power of laser radiation is determined.

Two techniques for the analysis of the interaction between particles in non-ideal quasi-equilibrium extended systems are considered. The first technique is based on a solution of the inverse problem describing the movement of dust particles by a system of Langevin equations. The second technique proceeds from the basic integral approaches of statistical physics. The conditions for the correct use of these techniques are presented, together with the results of their experimental application for the analysis of inter-grain interactions in the dusty plasma of radio frequency discharge.

In this paper, we discuss recent results concerning the electrical potential distribution around a small test charged particle in weakly ionized collisional plasmas in the presence of an ion flow. The effect of plasma absorption on the particle surface is taken into account and the results are compared with those from earlier models neglecting absorption. In the considered regime, the effect of plasma absorption is quite important and completely determines the long-range asymptote of the electrical potential.

The nonlinear amplitude modulation dynamics of electrostatic oscillations of massive charged defects in a three-component pair plasma is investigated, i.e. doped pair-ion plasmas (anticipating the injection of a massive charged component in the background, e.g. in fullerene experiments). Ion-acoustic oscillations in electron-positron-ion (e-p-i) plasmas are also covered, in the appropriate limit. Linear and nonlinear effects (MI, envelope modes) are discussed. The role of the temperature and density ratio between the pair species is stressed.