ISSN 0869-6632 (Print)
ISSN 2542-1905 (Online)

Журнал в журнале

Statistical properties of phase synchronization coefficient estimator

A phase synchronization coe?cient estimate, obtained from a time series, can take a high value even for uncoupled oscillators in the case of short signals and close basic frequencies. Since such situations are widespread in practice, it is necessary to detect them to avoid false conclusions about the presence of coupling. We investigate statistical properties of the estimator with the use of an exemplary system – uncoupled phase oscillators. Conditions leading to high probability to get big values of the estimator are determined quantitatively.

Studying of spatial transition to temporal chaos in active medium with unidirectional coupling

In the work a new model of a continuous active medium with unidirectional coupling of active elements is proposed. The Anishchenko–Astakhov oscillator was selected as an active element. The model shows both regular and chaotic in time regimes. The results  obtained for the medium are compared with the results for a chain of Anishchenko–Astakhov oscillators. The problem of conformity between the discrete model and the continuous medium is analyzed.

Synchronization of two coupled klystron active oscillators with delayed feedback

Results of experimental research of synchronization of two coupled almost identical resonance microwave active oscillators on multicavity klystrons in the modes of periodic and chaotic oscillations are presented. It is shown that depending on type of coupling it is possible to realize a mode of mutual frequency capture, synchronization by means of chaos full elimination by outer harmonic signal, and full synchronization mode. A possibility of using the chaos elimination e?ect for generation of sequence of chaotic radio pulses is shown.

Supercontinuum spectrum smoothing in the microstructure fibers with periodically modulated diameter

The results of numerical modelling of the supercontinuum generation in microstructure ?bers excited by femtosecond multi-soliton pulses are presented. Pulse dynamics is modelled using the extended Schrodinger equation, in which the dispersion and nonlinear coe?cient for given ?ber are calculated by plane wave method. It is more easy to achieve the phase-matching conditions for the dispersive wave generation in the ?bers with periodical modulated diameter.

The eigenwaves of the anisotropic photonic crystals: the calculation method and its features, the symmetry of the dispersion surface of the 2d crystal

Fully vectorial plane wave method is presented aimed the calculation of the electromagnetic eigenwaves in periodical dielectric media having arbitrary geometry and dimension with both isotropic and anisotropic elements. Using this method the e?ect of the reorientation of molecules of anisotropic material in photonic crystal on the dispersion surface is investigated.

Dynamics of probability amplitudes in hydrogen-like atoms under the action of strong variable electric field of electromagnetic wave accounting transitions to continuum

The dynamics of populations of 4s and 3p states in hydrogen atom is investigated under the action of ultra high laser single frequency linear-polarized pulse at one-, two- and three-photon resonance and at large detuning out of frame of perturbation theory and rotating wave approximation. It was shown the existence of low frequency modulation of optical oscillations,which frequency becomes zero at some values of laser ?eld amplitude.

Population dynamics in a hydrogen atom under the action of an ultra-short pulse of laser radiation

Population dynamics of highly excited states of a hydrogen atom under the action of an ultra-short intense laser pulse is studied by means of direct numerical solution of  Schr? edinger equation in the ?nite basis of eigenstates of the discrete and continuous energy spectrum. The essential role of continuous spectrum states is demonstrated. Formation of localized wave packets of Rydberg states is discussed.

Laser acceleration of heavy ion beams in vacuum

The possibility of heavy ion additional acceleration in laser beams is investigated. The main observation is the existence of a big variety of acceleration modes due to many ?tting parameters even for only one Gaussian beam and for crossed ones even more so. An essentially non-monotonic dependence of energy gain on relevant variables such as initial velocity or pulse duration is found which makes the search for the most e?ective acceleration modus very complex.