We present a dispersion relation for a plane-polarized electromagnetic wave in plasmas composed of cold electrons, relativistically hot electrons and bi-Maxwellian protons. It is shown that the free energy in proton-temperature anisotropy drives purely growing electromagnetic modes in our three-component plasma. Expressions for the growth rates and thresholds of instabilities are presented. The present results are relevant for explaining the origin of spontaneously generated magnetic fields in laboratory and astrophysical plasmas.

We present a derivation of the dispersion relation for electrostatic oscillations in a zero-temperature quantum plasma, in which degenerate electrons are governed by the Wigner equation, while non-degenerate ions follow the classical fluid equations. The Poisson equation determines the electrostatic wave potential. We consider parameters ranging from semiconductor plasmas to metallic plasmas and electron densities of compressed matter such as in laser compression schemes and dense astrophysical objects. Owing to the wave diffraction caused by overlapping electron wave function because of the Heisenberg uncertainty principle in dense plasmas, we have the possibility of Landau damping of the high-frequency electron plasma oscillations at large enough wavenumbers. The exact dispersion relations for the electron plasma oscillations are solved numerically and compared with the ones obtained by using approximate formulas for the electron susceptibility in the high- and low-frequency cases.

It is shown that the ponderomotive force of a large-amplitude electromagnetic wave in Rydberg plasmas can generate quasi-stationary magnetic fields. The present result can account for the origin of seed magnetic fields in the ultracold Rydberg plasmas when they are irradiated by the high-frequency electromagnetic wave.

We show that the non-stationary ponderomotive force of a large-amplitude electromagnetic wave in a very dense quantum plasma with streaming degenerate electrons can spontaneously create d.c. magnetic fields. The present result can account for the seed magnetic fields in compact astrophysical objects and in the next-generation intense laser–solid density plasma interaction experiments.

This work is based on a numerical study of particle transport and diffusion using ITER parameters. In particular, the effects of introducing a non-monotonic safety factor (NMSF) in the case of a reversed magnetic shear are shown. These results are compared with those found by using a monotonic safety factor (MSF). Double internal transport barriers are detected influencing the transport and diffusion of particles. The choices of the mode (m, n) and the m/n values play a dominant role for the particle diffusion, which leads to an improvement of the magnetic confinement.

Wave magnetic field components are measured across the radius (−10 cm ≤ r ≤ 10 cm) for a low-pressure (0.3 mbar) helicon discharge, in a toroidal vacuum chamber of small aspect ratio. Radial variation of the wave magnetic field components, measured during the helicon mode of the discharge, exhibit strong poloidal asymmetry which contribute significantly to the wave-induced helicity. The rise in the magnitude of the radial electric field with radiofrequency power, observed during discharge mode transition, supports better radial confinement of the plasma during the helicon mode of the discharge. The strong dependence of the plasma current on the helicon mode of the discharge has been observed during the present experimental study.

The Weibel instability, driven by a plasma temperature anisotropy, is non-resonant with plasma particles: it is purely growing in time, and does not oscillate. The effect of a counterstreaming plasma is examined. In a counterstreaming plasma with an excess of transverse temperature, the Weibel instability arises along the streaming direction. Here it is proved that for large wave-numbers the instability becomes resonant with a finite real (oscillation) frequency, ωr ≠ 0. When the plasma flows faster, with a bulk velocity larger than the parallel thermal velocity, the instability becomes dominantly resonant. This new feature of the Weibel instability can be relevant for astrophysical sources of non-thermal emissions and the stability of counterflowing plasma experiments.

Interaction between dust particles in a plasma is investigated on the basis of experimental pair correlation functions of dust formation in a dc glow discharge and the Poisson equation. It is shown that the calculated effective potentials have an oscillating character and depend rather weakly on macroscopic parameters of the plasma. Existence of an attractive component in the interaction of dust particles is confirmed within the validity range of our model.

In this paper two methods for determining plasma position in the IR-T1 tokamak are presented: a multipole moments method and an analytical solution of the equilibrium problem using the Grad–Shafranov equation. Based on the multipole moments method, modified Rogowski and saddle coils were designed and constructed for measuring plasma column displacement. Good agreement in comparison between the analytical and experimental approaches in determining plasma displacement in the IR-T1 tokamak is achieved.

The statistical analysis of heating effect and the cross-correlation analysis of both electron temperature and loop voltage have been done during electron cyclotron resonance heating (ECRH). The behavior of runaway electrons in the flat-top phase during ECRH are analyzed using experimental data. It is shown that the runaway population is indeed suppressed or even quenched when the toroidal electric field ET is reduced below the threshold electric field Eth by high-power and long-duration ECRH. The physical mechanism of runaway suppression is explored by the resonant interaction between the electron cyclotron waves and the energetic runaway electrons.

The dispersion properties of electrostatic surface waves propagating along the interface between a quantum magnetoplasma composed of electrons and positrons, and vacuum are studied by using a quantum magnetohydrodynamic plasma model. The general dispersion relation for arbitrary orientation of the magnetic field and the propagation vector is derived and analyzed in some special cases of interest (viz. when the magnetic field is directed parallel and perpendicular to the boundary surface). It is found that the quantum effects facilitate the propagation of electrostatic surface modes in a dense magnetoplasma. The effect of the external magnetic field is found to increase the frequency of the quantum surface wave. The existence of a singular wave on the boundary surface is also proved, and its properties are analyzed numerically. It is shown that the new wave characteristics appear due to the Rayleigh type of the wave.

Runaway transport is used to probe the magnetic fluctuation level for TEXTOR disruption plasmas. A zero-dimensional model of the current quench including the generation of runaway electrons has been applied to simulate the experimental current evolution during major disruptions [Plasma Phys. Control. Fusion50 (2008), 105007]. According to the loss rate of runaway electrons used in the fitting parameter of the zero-dimensional model, the magnetic fluctuation level in TEXTOR is derived. It is found that the magnetic fluctuation level is in the order of 10−5, and it increases with the atom number mixed into the plasma.

We perform a fully self-consistent three-dimensional numerical simulation for a compressible, dissipative magnetoplasma driven by large-scale perturbations, that contain a fairly broad spectrum of characteristic modes, ranging from largest scales to intermediate scales and down to the smallest scales, where the energy of the system is dissipated by collisional (ohmic) and viscous dissipations. Additionally, our simulation includes nonlinear interactions amongst a wide range of fluctuations that are initialized with random spectral amplitudes, leading to the cascade of spectral energy in the inertial range spectrum, and takes into account large-scale as well as small-scale perturbations that may have been induced by the background plasma fluctuations, as well as the non-adiabatic exchange of energy leading to the migration of energy from the energy-containing modes or randomly injected energy driven by perturbations and further dissipated by the smaller scales. Besides demonstrating the comparative decays of the total energy and the dissipation rate of the energy, our results show the existence of a perpendicular component of the current, thus clearly confirming that the self-organized state is non-force free.

Decaying electron magnetohydrodynamic (EMHD) turbulence in three dimensions is studied via high-resolution numerical simulations. The resulting energy spectra asymptotically approach a k−2 law with increasing RB, the ratio of the nonlinear to linear time scales in the governing equation, consistent with theoretical predictions. No evidence is found of a dissipative cutoff, consistent with non-local spectral energy transfer and recent studies of 2D EMHD turbulence. Dissipative cutoffs found in previous studies are explained as artificial effects of hyperdiffusivity. In another similarity to 2D EMHD turbulence, relatively stationary structures are found to develop in time, rather than the variability found in ordinary or MHD turbulence. Further, cascades of energy in 3D EMHD turbulence are found to be suppressed in all directions under the influence of a uniform background field. Energy transfer is further reduced in the direction parallel to the field, displaying scale-dependent anisotropy. Finally, the governing equation is found to yield a weak inverse cascade, at least partially transferring magnetic energy from small to large scales.