E. N. Egorov

Experimental and Theoretical Investigations of Stochastic Oscillatory Phenomena in a Nonrelativistic Electron Beam with a Virtual Cathode

Results are presented from experimental investigations of oscillatory phenomena in an electron beam with a virtual cathode in a diode gap with a decelerating field. Experiments have revealed a stochastic broadband generation of the microwave oscillations of a virtual cathode in a decelerating field. Numerical simulations based on a simple one-dimensional model have shown that the onset of the stochastic generation and the broadening of the oscillation spectrum with increasing beam deceleration rate are governed by the processes of regrouping of the electrons in a beam with a virtual cathode.

Microwave Generation Power in a Nonrelativistic Electron Beam with Virtual Cathode in a Retarding Electric Field

The power of microwave generation in a nonrelativistic electron beam with virtual cathode formed in a static retarding electric field (low-voltage vircator system) has been studied experimentally and by means of numerical simulation within the framework of a one-dimensional theory. The limits of applicability of the one-dimensional theory have been experimentally determined.

Analysis of the dependence of the microwave generation power of a low-voltage vircator on controlling parameters

The results of experimental and theoretical analysis of the dependence of the generation power of a low-voltage vircator, viz., a nonrelativistic electrovacuum device based on a high-intensity electron beam with a virtual cathode, on the values of controlling parameters are considered. The dependences of the generation power on the decelerating potential and on the beam current are analyzed.

Analysis of the formation of structures and chaotic dynamics in a nonrelativistic electron beam with a virtual cathode in the presence of a decelerating field

A nonrelativistic electron beam with a virtual cathode situated in the diode gap with a decelerating field is experimentally and theoretically studied. A 1D model of the electron beam in the presence of a decelerating field is constructed. Nonlinear nonstationary processes in this system are investigated by means of numerical analysis of the model. The processes are described and interpreted with regard to formation and interaction of structures in the electron flow. The theoretical results are qualitatively confirmed by the experimental data showing that the system under study can be considered as a promising controlled source of chaotic oscillations in the microwave range.

Investigation of the Chaotic Dynamics of an Electron Beam with a Virtual Cathode in an External Magnetic Field

The effect of the strength of the focusing magnetic field on chaotic dynamic processes occurring in an electron beam with a virtual cathode, as well as on the processes whereby the structures form in the beam and interact with each other, is studied by means of two-dimensional numerical simulations based on solving a self-consistent set of Vlasov-Maxwell equations. It is shown that, as the focusing magnetic field is decreased, the dynamics of an electron beam with a virtual cathode becomes more complicated due to the formation and interaction of spatiotemporal longitudinal and transverse structures in the interaction region of a vircator. The optimum efficiency of the interaction of an electron beam with the electromagnetic field of the vircator is achieved at a comparatively weak external magnetic field and is determined by the fundamentally two-dimensional nature of the motion of the beam electrons near the virtual cathode.

Dynamical control in multistable systems

The possibility of controlling oscillatory regimes in a dynamical system in which multistability is observed for certain values of the control parameters is considered for the Hénon map. It is shown that, in the case of such parametric action suppressing the undesired dynamic regime, the system either passes to a different state or exhibits unlimited growth of the dynamic variable characterizing the state of the system. The new regime is sensitive to small fluctuations of the phase of the parametric action.

Formation and nonlinear dynamics of the squeezed state of a helical electron beam with additional deceleration

Results of numerical simulations and analysis of the formation and nonlinear dynamics of the squeezed state of a helical electron beam in a vircator with a magnetron injection gun as an electron source and with additional electron deceleration are presented. The ranges of control parameters where the squeezed state can form in such a system are revealed, and specific features of the system dynamics are analyzed. It is shown that the formation of a squeezed state of a nonrelativistic helical electron beam in a system with electron deceleration is accompanied by low-frequency longitudinal dynamics of the space charge.

Emerging compressed states of a spiral electron stream in a system with deceleration

The emergence of a compressed state in an intense electron stream with additional deceleration in a virtual cathode formation mode is considered. The numerical-modeling results of compressed state formation are presented. It is shown that longitudinal oscillations of the density of the spatial charge of a beam may be observable in a system with deceleration in a compressed state.

Virtual cathode formation in helical electron flow under the action of intrinsic space-charge field

The process of virtual cathode formation in an annular helical electron beam formed by a magnetron-injector gun has been numerically simulated in the regime of small pitch factors with allowance for the intrinsic space-charge field.

Experimental and Theoretical Study of Chaotic Microwave Oscillations and Pattern Formation in Non-relativistic Electron Beam with Virtual Cathode

Results are presented from experimental and numerical study of oscillatory phenomena in electron beam with virtual cathode (VC) in diode gap with decelerating field. Experiments have revealed a chaotic broadband generation of the microwave oscillations of VC. Numerical simulations based on a simple PIC model have shown that the onset of the chaotic generation with increasing beam deceleration rate are governed by the processes of regrouping of the electrons in the beam with VC