[en] The formation of lithium clusters in a helium flow is considered within the method considering the widths of energy levels. It is shown that lithium atoms in a plasma flow of inert helium form a cluster consisting of lithium only. In addition to lithium clusters with interatomic distances corresponding to interatomic distances of the equilibrium state, long-lived excitations of clusters with interatomic distances of 13 Bohr radii are observed. However, if excitations are removed, such systems transfer into the ground state or decay. In addition, it is observed that Li–He systems are long-lived under conditions of external excitations but quickly lose helium when these excitations are removed.

No abstract available

[en] This paper discusses some aspects of cosmological expansion as viewed by an observer. It identifies the rate of change of the angular distance v_Θ with respect to the observer's clock as a crucial quantity in properly understanding the expansion. Using this quantity and the angular distance, in addition to the traditional approach to visualization, provides a more vivid picture of the cosmological expansion and is key for adequately visualizing it. (methodological notes)

[en] A nonlinear theory of Doppler reflectometry is developed in the case of a high level of turbulent density perturbations, when the multiple forward scattering of the probing wave is dominant. It is shown that even in this regime the diagnostics is able to measure the plasma poloidal velocity with a spatial resolution that is, however, dependent on the plasma density profile and the turbulence distribution. The problem of diagnostics results interpretation is discussed

[en] It is demonstrated that low-temperature weakly-ionized nonequilibrium plasma created by a high-energy electron beam in gases (gas mixtures) with the Ramsauer minimum in a transport cross section and the effective attachment of slow electrons can be used as a medium for the amplification of electromagnetic radiation in the subterahertz frequency band. An analysis of the electron energy distribution function (EEDF) in a Xe : F_2 mixture is performed. An energy interval with a growing EEDF is found to exist in such a mixture. Such an interval provides the existence of the population inversion of the electron spectrum in the continuum and is responsible for the positive value of a gain factor for microwave radiation. A gain factor depending on amplified radiation frequency and plasma parameters is analysed. (paper)

[en] The dynamics of an atom in a strong single mode non-classical electromagnetic cavity field is studied. The reconstruction of the energy spectrum of atom and the effect of the ionization suppression in the presence of non-classical field are discussed. It is found that Kramers – Henneberger mechanism of the ionization suppression is realized in strong nonclassical fields also. For squeezed vacuum states the threshold of the stabilization is approximately three times lower than for classical (coherent) state of the same intensity

[en] The dynamics of an atom in a strong single mode non-classical electromagnetic cavity field is studied. The reconstruction of the energy spectrum of an atom and the effect of ionization suppression in the presence of a non-classical field are discussed. It is found that a mechanism of ionization suppression similar to the Kramers–Henneberger one is also realized in strong non-classical fields. For squeezed vacuum states the threshold of the stabilization is approximately three times lower than for a classical (coherent) state of the same intensity. (paper)

[en] The effect of interference stabilization of Rydberg atoms in a high-intensity IR laser field is proposed to create a plasma channel with population inversion for conversion of the input laser energy into the VUV and XUV frequency band. (letter)

[en] Theoretical investigations of the electronic structure, synthesis, and all-optical magnetization switching of transition-metal silicide nanostructures are reported. The magnetic moment of the nanostructures is studied as a function of the silicide cluster size and configuration. The experimentally demonstrated magnetization switching of nanostructured nickel silicide by circularly polarized light makes it possible to create high-speed storage devices with high density data recording

[en] The review is devoted to plasma structures with an extremely small transverse size, namely, thin current sheets that have been discovered and investigated by spacecraft observations in the Earth’s magnetotail in the last few decades. The formation of current sheets is attributed to complicated dynamic processes occurring in a collisionless space plasma during geomagnetic perturbations and near the magnetic reconnection regions. The models that describe thin current structures in the Earth’s magnetotail are reviewed. They are based on the assumption of the quasi-adiabatic ion dynamics in a relatively weak magnetic field of the magnetotail neutral sheet, where the ions can become unmagnetized. It is shown that the ion distribution can be represented as a function of the integrals of particle motion—the total energy and quasi-adiabatic invariant. Various modifications of the initial equilibrium are considered that are obtained with allowance for the currents of magnetized electrons, the contribution of oxygen ions, the asymmetry of plasma sources, and the effects related to the non-Maxwellian particle distributions. The theoretical results are compared with the observational data from the Cluster spacecraft mission. Various plasma instabilities developing in thin current sheets are investigated. The evolution of the tearing mode is analyzed, and the parameter range in which the mode can grow are determined. The paradox of complete stabilization of the tearing mode in current sheets with a nonzero normal magnetic field component is thereby resolved based on the quasi-adiabatic model. It is shown that, over a wide range of current sheet parameters and the propagation directions of large-scale unstable waves, various modified drift instabilities—kink and sausage modes—can develop in the system. Based on the concept of a turbulent electromagnetic field excited as a result of the development and saturation of unstable waves, a mechanism for charged particle acceleration in turbulent current sheets is proposed and the energy spectra of the accelerated particles are obtained.