Stabilization of bound state decay in an intense monochromatic high-frequency field

The formalism of complex quasienergies is used for exact calculation of the field-dependent decay rate for a weakly bound particle (in the model of a three-dimensional zero-range potential) in a strong monochromatic laser field. It is shown that the adiabatic (quasistationary) stabilization regime in this model occurs at frequencies ω exceeding the binding energy and only in a limited intensity range. A simple estimate is obtained for the critical field of stabilization breakdown. The effect may be observed for the decay of H^? ions in the field of a neodymium laser of femtosecond duration.     

Role of exchange and magnetostatic interactions in the effect of thermal magnetization of fine-crystalline alloys of highly anisotropic magnetics

The theory of micromagnetism has been applied to a system consisting of plane-parallel layers of a monoaxial magnetic which differ by the orientation of easy magnetization axes to numerically investigate the effect of thermal magnetization which was simulated by varying the anisotropy constant. It has been revealed that the effect of thermal magnetization does not show up if the exchange interaction between the layers is disregarded. An enhancement of magnetostatic interaction, which was simulated by increasing the degree of noncomplanarity of the easy magnetization axes in the system layers results in a reduction of the effect. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 8, pp. 8–11, August, 2007.     

Self-induced transparency in limited media

A theory is constructed of self-induced transparency for a surface wave, propagating on the boundary surface of two media, one of which is a resonance one, and also for a localized TE-mode in dielectric waveguide, containing non-intersecting two-level atoms. An evident expression is found for a pulsing solition, formed in these conditions, in terms of initial data.     

Three-dimensional model of relativistic-invariant field theory,integrable by the Inverse Scattering Transform

In the space-time with signature (2,2) the self-duality equations in the specific case of potentials independent of one of the coordinates are reduced to a relativistic-invariant system in the (2-1)-dimensional space-time. A general solution of this system is constructed by means of IST. A soliton solution, finite in all directions, is discussed. It is found that there is no classical scattering of both solitons and continuous spectrum waves.     

Model potential for calculation of multiphoton processes in diatomic molecules

The model potential, analogous to the Fues atomic potential is suggested for analytical calculation of the perturbation theory matrix elements, defining interaction of molecule with electromagnetic field. The explicit expressions for the Green and wave functions of the molecular optical electron are received.     

Acoustic spectroscopy of fluid saturation effects in carbonate rock

The results of acoustic spectroscopy of a carbonate sedimentary rock in the case of saturation degree variations are given. The data on the elasticity and dissipation tensors within a two-octave range are obtained for one and the same sample using one and the same measurement technique. High accuracy of the measurements allowed distinguishing all three saturation stages, namely, condensation, meniscus creation, and pore filling with a fluid. The observed variations are in good agreement with the results of a standard granulometric analysis. The character of variations in the frequency dependence of attenuation coefficients make it possible to make reasonable assumption concerning the mechanisms responsible for acoustic energy absorption in porous materials.     

Threshold phenomena in electron-atom scattering in a laser field

Effective-range theory is developed to describe the processes of multiphoton bremsstrahlung absorption and the emission of laser radiation that accompanies the scattering of electrons from atoms in a laser field. It is found that the cross sections for multiphoton absorption in the plateau region increases resonantly for electron energies corresponding to the thresholds of induced bremsstrahlung (i.e., multiples of the photon energy). It is shown that this effect is caused by the laser-field modified threshold phenomena in the cross sections for multichannel reactions (Baz’ threshold anomalies).