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

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Numerical simulation of nonlinear dynamics in multiple cavity klystron oscillator with delayed feedback by the "partikle-in- cell» method

The 1.5 D code program of numerical simulation of nonlinear nonstationary processes in the klystron-type devices based on the nonstationary L.A. Vainshtein’s theory of cavity excitation and the «particle-in-cell» method for modeling of the electron beam dynamics is developed. The results of numerical simulation of the basic oscillation modes of the fourcavity klystron oscillator with the external delayed feedback are presented.

Experiments with a source of chaos – a radio­electronic device with square­law phase modulator and interference amplification of quasi­harmonic signal

A modified radio­electronic analog of the nonlinear ring cavity is realized in laboratory. The device represents a special class of oscillations or waves sources. An operation principle of the sources is based on interference amplification of feedback signal by an input signal. A laboratory experiments are performed, the likeness of their results and simulation data is shown. An intermittency, chaos, regular, static modes are detected. A thesis on controlled nonlinearity of dynamical systems is suggested.

Chaos in radio device with square­law phase modulator and interference amplification of quasi­harmonic signal: a model and simulation

The attempt is undertaken to define a class of oscillations or waves sources, the operation principle of which is based on interference amplification of feedback signal by an input signal. The precedent here is the optical Ikeda’s system. The radio­electronic analog of a nonlinear ring interferometer and it modification are offered, the block diagrams and mathematical models are constructed. The computer simulation is performed. An intermittency, chaos, regular, static modes are detected.

Reflex klystron as an example of a self­oscillating delayed feedback system

Nonstationary theory of the reflex klystron oscillator based on differential equation with delay is developed. Analysis of self­excitation conditions, steady­state oscillation regimes and their stability is presented. Application of the developed theory for calculating of output characteristics of micromachined submillimetre­band reflex klystron is presented as well. Theoretical results are compared with the results of numerical simulation based on the particle­in­cell method.

Reconstruction of ensembles of coupled time-delay systems from time series

The methods for the reconstruction of model delay-differential equations for ensembles of coupled time-delay systems from their time series are proposed. The methods efficiency is illustrated using chaotic and periodic time series from chains of diffusively coupled model and experimental time-delay systems for the cases of unidirectional andmutual coupling.

Automodulation and chaotic regimes of generation in a two-resonator gyroklystron with delayed feedback

Topic and aim. The dynamics of a double-resonator gyroklystron of the 93 GHz band with delayed feedback is studied. A comparative analysis of the dynamical regimes of amplifier generation obtained in the numerical experiment both on the basis of averaged equations and in the framework of direct numerical simulation by the «particle-in-cells» method using the KARAT code is carried out. Method. To identify the dynamical properties of system behavior we apply the spectrum of of statistical methods from the theory of chaos: the calculation of fractal dimensions, Lyapunov exponents, etc.