Structure formation and control of electron beam dynamics in triode systems with virtual cathode

Abstract

In recent years the researches of various sources of microwave radiation with supercritical currents are actively investigated. Operation of these devices is based on virtual cathode (VC) formation in the interaction space. VC is the oscillating area with space charge potential close to a potential of an electron source. Appearance of VC results in strong modulation of the arriving electron beam and excitation of high-power oscillations. The design simplicity, ultra high level of radiation power, possibility of frequency tuning with modification of electron beam parameters has attracted significant interest in recent years. In the present work we consider a triode-like vircator. In this system the electron beam injects from a cathode surface, further it passes an accelerating potential and after transmitting through an anode grid, it arrives in equipotential interaction space. One of remarkable features of VC devices is the complex irregular character of output radiation in similar devices. The great success of the nonlinear dynamic systems theory in the recent years is the discovery of a strong connection between dynamical chaos and structure formation. It is very interesting to clarify the connection between the formation of structures in electron beam with VC and its complex dynamics. The understanding of this connection allows us to control generation regimes at the expense of action on electronic structures.