The Hall effects are suggested to be responsible for the decoupling of electrons and ions of magnetic plasma in the process of magnetic reconnection. However, the process that ultimately causes the electrons to diffuse from the magnetic field in the very small diffusion region remains one of the main unsolved problems in magnetic reconnection theory. In this paper, the structure of the Hall electric field in the diffusion region is studied theoretically in the coordinate system located on the magnetic line. A numerical simulation result for this problem is also given. The new discovery is that electrons can be generated in the diffusion region due to the Hall effects. Therefore the role of the Hall effects in the decoupling of electrons and ions of a magnetic plasma can be clarified in the structure of the Hall electric field.

The resonant interaction of a narrow electron beam spiraling in a cold homogeneous magnetized plasma with electromagnetic cylindrical waves is considered. The conclusions derived in recent papers about the formation, in the presence of effective electromagnetic energy dissipation out of the radially bounded beam, of dynamically stable and longtime living bunches of resonant electrons in the developed stage of their nonlinear interaction with the waves are discussed in this paper for more general physical cases and for wider ranges of characteristic parameters. General analytical formulas for the excited electromagnetic fields, the radiated electromagnetic power flux and the linear growth rate as well as relevant numerical simulations results are presented.

The existence of arbitrary amplitude nonlinear electrostatic waves is investigated for a plasma with positively charged dust in the presence of two-temperature electron species. It is shown that such a plasma supports both soliton and double layer structures.

The existence of large-amplitude dust-acoustic double layers is investigated in an unmagnetized dusty plasma comprising a negatively charged warm dust fluid, non-thermal ions and Boltzmann electrons. It is found that the non-thermal plasma supports the existence of rarefactive double layers only. The dependence of the double-layer amplitude and Mach number on various parameters such as the non-thermal parameter, dust temperature and electron concentration is numerically examined.

An analysis of self-fields associated with charge and current densities of the electron beam in a free-electron laser with helical wiggler and axial magnetic field is presented. The self-electric field is derived from Poisson's equation. A more detailed analytical model for the self-magnetic field is determined from Ampere's law. Mutual influence of the electron velocity and self-magnetic field is considered to account for the total self-magnetic field. It is shown that for group I orbits, the self-magnetic field acts as a diamagnetic correction to the wiggler magnetic field; for group II orbits, it acts as a paramagnetic correction. Both diamagnetic and paramagnetic effects become stronger near the transverse velocity resonance. An important effect of the self-fields on the electron trajectories is the creation of unstable orbits for group II, which are not found in the absence of self-fields.

Most of the mode conversion theories considered so far assume only a plane-layered medium, i.e. a medium where the parameters depend on one spatial coordinate. We generalize the mode-conversion method of Cairns and Lashmore-Davies to plasmas with two-dimensional inhomogeneities. In the method presented here, the frequencies $\omega_1$ and $\omega_2$ of the uncoupled modes belonging to two different dispersion equations are considered as functions of the space variable $\mathbf r$ and the wave vector $\mathbf k$ and are coupled together via a small quantity $\eta$. We calculate the energy transmission and conversion coefficients analytically by solving two coupled wave amplitude equations in the electron cyclotron range of frequencies. The results are applicable to electron Bernstein wave heating of plasmas with two-dimensional inhomogeneity, e.g. spherical tokamaks.

In the Lorentz–Vlasov model of a plasma the ions are assumed to be fixed in space with disordered distribution, and the Coulomb interaction between electrons is approximated by the Vlasov field, calculated self-consistently from the electron position–momentum distribution function. If correlations between ions are neglected, then the dynamical conductivity of the plasma may be evaluated from the dynamics of the electron gas in interaction with a single ion, the remaining ions being approximated by a uniform background. In dielectric or energy-loss theory, the dynamical friction coefficient is expressed in terms of the dielectric function of the uniform electron gas. A more detailed theory must take full account of the scattering of electrons by the selected ion. It is shown for an electron gas at zero temperature and metallic density, and for a simple ion pseudopotential, that the frequency dependence of the friction coefficient differs appreciably from that predicted by energy-loss theory.

The momentum balance equations and the balance equations for the pressure tensors of a collision-free multi-species magnetoplasma are linearized and Fourier-transformed, together with Maxwell's curl equations. They are combined in an algebraic dispersion system for the electric wave vector. The vanishing determinant of this system is the dispersion equation. It is of degree $2+3s$ in the square of the refractive index if $s$ is the number of different particle species.

This paper presents an investigation of the filamentation process of a uniform plane Alfvén wave for a compressible magnetohydrodynamics case, when a transverse perturbation (perturbation having non-uniform intensity distribution in a plane perpendicular to the direction of wave propagation) is present on it. The physical mechanism of the filament formation is discussed in detail with the applications to the Solar wind turbulence and the coronal heating. The dependence of the critical field of the perturbation, its critical transverse size and the formation of filaments, on the plasma $\beta $, main Alfvén field and other parameters has been studied in detail.

A general nonlinear theory for low-frequency electromagnetic field generation due to the action of non-uniform and non-stationary high-frequency electromagnetic radiation (ponderomotive force) in uniform multicomponent dusty magnetoplasmas is developed. The anisotropic thermal pressure of all species in slow and fast oscillations is taken into account. This theory permits us to consider the nonlinear action of all waves that can exist in such plasmas. As an example, the equations for dust particle velocities arising due to nonlinear electric fields induced by electromagnetic cyclotron waves travelling along an external magnetic field are obtained. The dust grains are considered to be magnetized as well as unmagnetized. Various regimes of dust grain dynamics depending on the spatio-temporal variation of a fast wave amplitude are discussed. It is shown that induced nonlinear electric fields can have both an electrostatic and an electromagnetic nature. In some cases these fields across the background magnetic field in warm plasmas are considerably larger than those in cold plasmas. The longitudinal nonlinear electric field remains the same in warm and cold plasmas in its order of magnitude. Regimes are found for which the transverse acceleration of dust grains is much larger than the longitudinal one.