Interaction of kinks for semilinear wave equations with a small parameter

We consider a class of semilinear wave equations with a small parameter and nonlinearities such that the equations have exact kink-type solutions. The main result consists in obtaining sufficient conditions for the nonlinearities under which the interaction of kinks preserves the sine-Gordon scenario. This means that the interaction occurs without changing the waves shape and with shifts of trajectories.     

Specific Features of Thermochemical and Rate Processes on Destruction of Chemical Munnition

The prospects for using laser beam technologies for disposal of chemical munnition are considered within the framework of works on the destruction of chemical weapons. A single-stage technology of destruction of the subelements of chemical munnition in molten aluminum inside a furnace-armored chamber is described. The rate and the thermochemical processes proceeding during the thermal decomposition of the components of an munnition subelement are analyzed in detail and the yield of secondary harmful substances is calculated. All sources of the secondary harmful substances formed during the thermal treatment of the cases of air chemical munnition are revealed. The chemical composition of the medium inside the heat chamber during treatment of cases of various types of munnition is calculated. The requirements for the purification system of waste gases are determined on the basis of a detailed analysis of all nomenclature of the cases to be treated.     

Classification of cocycles of generic equivalence relations

We study cocycles of an ergodic generic countable equivalence relation ℜ modulo meager sets. Two cocycles of ℜ are called weakly equivalent if they are cohomologous up to an element of Aut ℜ. It is proved that two nontransient cocycles with values in an arbitrary countable group are weakly equivalent if and only if their generic Mackey actions are isomorphic.     

Ionization self-compression of intense femtosecond pulses propagating through gas-filled dielectric capillaries

A mechanism of the ionization-induced self-compression of femtosecond laser pulses propagating in a gas-filled hollow dielectric capillary has been investigated both experimentally and theoretically. In particular, the double self-compression of a laser pulse from 76 to 40 fs has been experimentally demonstrated. A theoretical model that explains the mechanism of such a self-compression and provides a good agreement with the experimental data has been developed. The model also predicts that a laser pulse shorter than 10 fs can be generated in the optimal regime with an energy efficiency exceeding the efficiency of self-compression on a filament widely discussed at present.     

Ten-Megawatt Pulsed Gyrotron with a 1-cm Wavelength and a 50% Efficiency

Development of a gyrotron driven by a relativistic electron beam and generating radiation at the wavelength 1 cm with an output power of 10 MW, an efficiency of 50%, and a pulse duration of a few hundreds of nanoseconds is reported.     

Generation of squeezed states on reflection of light from a system of free electrons

The statistical characteristics of an electromagnetic wave reflected from a system of successive free-electron mirrors are investigated. Such a configuration of the electron stream is characteristic in particular for free-electron lasers. An expresson is obtained for the squeeze factor of the field of the reflected wave, and the optimal geometric configuration of the system of electrons is found. Numerical estimates show that the squeezing can be substantial when the number of electronic mirrors is large. Pis’ma Zh. éksp. Teor. Fiz. 63, No. 3, 160–165 (10 February 1996)     

Remote monitoring of surfaces of optical elements

Potentialities for remote measurement of parameters of working surfaces of optical elements and remote detection of the appearance of defects of such surfaces are studied experimentally. The method suggested in this paper is based on the use of a nonlinear optical image intensifier consisting of a phase-conjugating mirror and laser preamplifiers. A sensitivity of about two signal photons per pixel limited by the quantum noise level is achieved in remote measurements of the angular distribution of diffuse reflection from optical surfaces.     

Properties of evanescent waves in polarized media in a constant external electric field: II. The noncompensated antiferromagnetic

The effect of gyrotropy on the character of formation and propagation of evanescent waves of the TM and TE types in the presence of a constant external electric field is studied by an example of the two-sublattice model of a centrally symmetric antiferromagnetic in the easy-plane, weak ferromagnetic phase.     

Ab initio calculation and spectral properties of nano- and bulk materials

This paper presents the development of ab initio calculation of the electronic structure of either clusters, nano-crystals, doped and unperfected bulk crystals. In addition, analysis of selected experimental data for γ- or plasma irradiated pure and doped wide-band gap oxides such as sapphire, α-Al₂O₃, garnet, Y₃Al₅O₁₂, Gd₃Sc₂Al₃O₁₂ and perovskites YAlO₃, SrTiO₃ is presented. Change in the crystals surface morphology and spectroscopic properties of sapphire, perovskites, garnets as well as ion oxidation state in pure and doped γ- and plasma irradiated crystals are discussed in detail using the optical and X ray spectroscopy experimental results.     

Spin field emission and state switching in a magnetic tunnel junction

The phenomena of spin tunneling and spin torque transfer between magnetic layers of a tunnel spin-valve setup under weak and strong field emissions of spin-polarized electrons are considered. Bifurcational features of changes in the macrospin states under the impact of a tunnel current are discussed for varying directions of the spin-polarization vector.