Experimental and theoretical investigations of stochastic oscillatory phenomena in a nonrelativistic electron beam with a virtual cathode

Abstract

-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.

Investigation of the chaotic dynamics of an electron beam with a virtual cathode in an external magnetic field

“…In addition, the vircator radiation spectra calculated in 1D models are in rather poor agreement with the data of physical experiments. In particular, it was shown experimentally that the bandwidth of chaotic generation in a vircator is f / f 0 > 50% [12], and, in some experiments, radiation was observed to be generated over more than an octave bandwidth [25,26]. It can be supposed that this disagreement stems from the fact that, in 1D models, transverse electron motions in a beam focused by a weak (but finite) magnetic field are ignored.…”

Intermittency route to chaos and broadband high-frequency generation in semiconductor superlattice coupled to external resonator

“…These characteristics match or even exceed similar parameters of other solid-state and vacuum sources of chaotic signals [25,[63][64][65][66][67][68]. The latter makes the SL coupled to a resonator promising for using it as a key element in broadband sources of chaotic microwaves or fast random number generators [20,27,43,69], which could have applications in high-speed chaotic communications and spreadspectrum spectroscopy.…”

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

“…In contrast to conventional vircators, which employ the relativistic beams and whose pulse power ranges from several tens to several hundreds of megawatts [13], these oscillations are characterized by a significantly lower power. (In [17], the integral continuous-wave power of the oscillations in a nonrelativistic beam with a VC formed in the presence of a decelerating field is a few watts for the centimeter wave range. )…”

“…The significance of this problem has been indicated in a substantial number of related works (see, for example, [1][2][3][4][5][6][7][8][9][10]). This study is important for the fundamental investigation processes governing formation of the chaotic dynamics and structures in the beam-plasma systems [5,6,8,9,[11][12][13], for the applied analysis related to the development and optimization of the VC-based high-power microwave oscillators (vircators) [4,5,8,14], for acceleration of charged particles with an oscillating VC [15,16], and for creation of the sources of broadband noiselike radiation with different power levels [10,17].…”