Conferences. Meetings. Symposia. Scientific Schools

A brief review of reports at the V Congress of Biophysicists of Russia (Rostov-on-Don, 4–10 October 2015) is presented in which the results are based on the methods of nonlinear dynamics. Stochastic methods are widely represented obtaining new results in neurodynamics and theory of molecular motors. Molecular dynamics simulations include now not only dynamics of separate molecules, but complex molecular systems like ion channels incorporated in lipid membrane.

This article contains the information concerning the organization of the All-Russian scientific school in the Saratov State University for young scientists. The paper deals with the reviews of the lectures, labs, practical tasks, etc. The scientists from different regions of Russia have taken part in this school.

We present the mathematical models, computer code and numerical analysis for modeling linear operation regimes of broadband helix travelling­wave tube (TWT) with the inhomogeneous slow wave structure along the interaction space. One­dimensional model of the interaction of the forward and reflected electromagnetic waves with an electron beam in a inhomogeneous section of the slow wave structure was researched. The calculation method of the linear gain and self­excitation conditions of multisection TWT was suggested.

In a gyrotron with quasi­optical mode convertor, apart from the fundamental mode, excitation of a mode with opposite azimuthal rotation of the field occurs due to the wave reflected from the remote load. Interaction of the two oppositely rotating modes is investigated by using the quasi­linear equation for slowly varying amplitudes. The developed theory allows explanation of the experimental results where periodic modulation of the transverse structure of gyrotron radiation partially reflected from a remote oscillating membrane was observed.

Several mathematical models of volume free electron lasers are described with the aim of investigation of their nonlinear dynamics. This review includes models of beams of charged particles moving through spatially­periodic systems (photonic crystals). In simulation of volume free electron lasers on the base of photonic crystals made from metallic threads or foils working in the microwave range it was shown the necessity of taking into account dispersion of electromagnetic waves on resonator threads.

The analysis of influence of the reflection coefficient of the electromagnetic field from the cathode on the radiation characteristics of Cherenkov generators was carried out by the methods of computer simulation. It is shown that the optimal parameters of generation can be achieved at the values of the reflection coefficient close to unity.