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We consider the problem of radiation from a traveling-wave antenna in a warm electron plasma which moves along a strong magnetic field at a constant velocity. To describe the electromagnetic properties of the plasma, we use the diagonal tensor of dielectric permittivity, which is calculated for a magnetized plasma with the Maxwellian electron velocity distribution allowing for collisions of electrons with neutral molecules. The dispersion relation is analyzed numerically, and expressions for the field amplitudes in the wave zone are obtained. The radiation resistance of the antenna is calculated. It is shown that as the phase velocity of the traveling current wave in the antenna approaches the average velocity of the plasma motion, the radiation field decreases exponentially with distance from the source as a result of the efficient transfer of the wave energy to the plasma electrons due to collisionless interaction. [ABSTRACT FROM AUTHOR]

We generalize the equations, which describe the backward-wave oscillator regime in the magnetized plasma in the presence of a jump (“step”) in the velocity distribution function of energetic charged particles, to the case of an arbitrary direction of the wave relative to an external magnetic field and an arbitrary wave mode. The dependence of instability threshold on the angle χ between the wave vector k and the external magnetic field B0 for whistler-mode waves and a slow extraordinary wave (Z-mode) is determined. [ABSTRACT FROM AUTHOR]

The dispersion law and the anomalous magnetic moment of a neutrino in a magnetized electron-positron plasma are investigated as functions of the magnetic field strength, the polarization state, energy, direction of motion, and mass of the neutrino, and the parameters of the plasma. The calculation was performed by the method of the time Green's functions at finite temperature. Results for a massive neutrino in the limiting case are compared with the results of other authors, obtained earlier for a massless left-handed neutrino. [ABSTRACT FROM AUTHOR]

The phenomenon of magnetic flux breakthrough into a wire array during its implosion was studied experimentally at the Angara-5-1 facility. It is shown that breakthroughs develop in the final stage of plasma production from the wire material and occur near the initial wire position. The spatial distributions of the azimuthal magnetic field within tungsten, molybdenum, copper, and aluminum wire arrays were studied using magnetic probes. The distributions of the azimuthal magnetic field B( z, t) along the array height in different stages of implosion were measured, and the characteristic dimensions of regions with a nonuniform magnetic field that appear during magnetic flux breakthroughs at the outer boundary of the wire array plasma were determined. The dimensions of these regions are compared with those of the regions with depressed plasma radiation observed in frame and time-integrated X-ray images. The dynamics of the distribution B( z, t) in regions with a nonuniform magnetic field during breakthroughs of the azimuthal magnetic flux is compared with that of the spatial distribution of pinch radiation in the frame X-ray images in different stages of implosion. The experimental data on the characteristics of spatially nonuniform breakthroughs of the magnetic flux into the wire array are analyzed using the plasma rainstorm model proposed by V.V. Aleksandrov et al. (JETP 97, 745 (2003)). The plasma density in the region of magnetic flux breakthrough is estimated. [ABSTRACT FROM AUTHOR]

Consideration was given to the design and mathematical modeling of the stabilization system for unstable vertical position of plasma in the T-15 tokamak (Institute of Tokamak Physics, National Research Centre 'Kurchatov Institute'). For suppression of vertical instability of plasma, the poloidal systems of vertically elongated tokamaks were analyzed with the aim of detecting the most efficient positioning of the winding of the horizontal magnetic field (fast winding) in the T-15 tokamak. The controllability domains of vertical shift of the plasma magnetic axis were estimated for various arrangements of the fast winding (i) outside the toroidal winding, (ii) between the toroidal winding and the vacuum chamber, (iii) inside the tokamak vacuum chamber. Part I considered the linear control system for vertical plasma position where the fast winding is located outside the tokamak toroidal winding. For the given configuration of the poloidal system, the control system of the T-15 tokamak was shown to be inherently unstable. Inherent system stability is attained by using a multidimensional control system where all windings of the central solenoid and the windings of the poloidal field are used to control the vertical plasma position and the current in the fast winding. [ABSTRACT FROM AUTHOR]

Nonlinear modification of the plasma magnetospheric density near the dayside magnetospheric boundary, caused by the ponderomotive force induced by ULF geomagnetic pulsations, has been studied analytically and numerically. An expression for the ponderomotive force, which differs from the previous similar results, has been obtained. It has been indicated that the well-known Pitaevskii formula for magnetic moment is incomplete. The action of the ponderomotive, gravitational, and centrifugal forces on magnetospheric plasma modification in a two-dipole geomagnetic field according to the (Antonova and Shabanskii, 1968) model has been considered. [ABSTRACT FROM AUTHOR]

Self-organization and evolution of magnetoplasma structures in the upper layers of the solar convection zone are discussed as a process of diffuse aggregation of magnetic flux tubes. Equations describing the tube motion under the action of magnetic interaction forces, hydrodynamic forces, and random forces are written explicitly. The process of aggregation of magnetic flux tubes into magnetic flux clusters of different shapes and dimensions is simulated numerically. The obtained structures are compared with the observed morphological types of sunspot groups. The quantitative comparison with the observational data was performed by comparing the fractal dimensions of the photospheric magnetic structures observed in solar active regions with those of structures obtained in the numerical experiment. The model has the following free parameters: the numbers of magnetic flux tubes with opposite polarities on the considered area element ( Nn and Ns), the average radius of the cross section of the magnetic flux tube ( a), its effective length ( l), the twist factor of the tube field ( k), and the absolute value of the average velocity of chaotic tube displacements ( d). Variations in these parameters in physically reasonable limits leads to the formation of structures (tube clusters of different morphological types) having different fractal dimensions. Using the NOAA 10488 active region, which appeared and developed into a complicated configuration near the central meridian, as an example, it is shown that good quantitative agreement between the fractal dimensions is achieved at the following parameters of the model: Nn = Ns = 250 ± 50; a = 150 ± 50 km; l ∼ 5000 km, and d = 80 ± 10 m/s. These results do not contradict the observational data and theoretical estimates obtained in the framework of the Parker 'spaghetti' model and provide new information on the physical processes resulting in the origin and evolution of local magnetic plasma structures in the near-photospheric layers of the solar convection zone. [ABSTRACT FROM AUTHOR]