Effect of the electron beam modulation on the sub-THz generation in the vircator with the field-emission cathode

Abstract

In this paper, we focus on the numerical investigation of the vircator with a controlling emission from a field-emission cathode. The external harmonic signal is added to the accelerating electric field in the beam formation region and effects on the beam emission process leading to the electron emission modulation. As a consequence, the beam is injected into the drift chamber of the vircator being density-modulated. The strong influence of the modulation parameters (modulation depth and frequency) on the characteristics of virtual cathode oscillations has been discovered. We have shown that the tuning of the modulation frequency to the harmonics of the basic frequency of virtual cathode oscillations leads to the considerable power increase of its higher harmonics in the output spectrum.

Processes of virtual cathodes interaction in multibeam system

“…A possible solution to the problem of the vircator generation frequency increase is to develop new generator schemes that are based on a virtual cathode. [11][12][13][14][15] Specifically, this paper describes the development and analysis of a multibeam vircator system. Thus, the idea of creating several VCs in the vircator drift space (by injecting several electron beams with supercritical currents) to increase power of higher-frequency spectral components via the interaction (synchronization) between VCs seems promising.…”

The development and interaction of instabilities in intense relativistic electron beams

“…39,40,42 Nowadays, a rising interest in the research of vircators is caused by their advantages: a very high output microwave radiation power, a simple construction (in particular, vircators can operate without external focusing magnetic field), short rise time, the possibility of a simple frequency tuning and regime switching (tunability), a rather short operation region, and low requirements to the quality of the electron beam. 1,14,15,[43][44][45][46][47][48][49][50] The last property is of great importance when an oscillator is fed with a short and lowquality beam formed by an explosion emission electron injector. 51,52 a) Electronic mail: KurkinSA@gmail.com…”

Численное Моделирование Возможности Увеличения Эффективной Плазменной Частоты При Формировании Сжатого Состояния Пучка

“…Для продвижения подобных устройств в более высокочастотный диапазон требуется исследование вопросов повышения частоты генерации в системах с виртуальным катодом. Типичные значения рабочих частот виркаторов лежат в диапазоне 1...10 ГГц, хотя в последнее время показано, что, используя эффекты генерации высших гармоник [13] или переключения пучковых мод [7], можно повысить рабочие частоты подобных систем до 40...80 ГГц. Фундаментальным ограничением частоты виркаторов является тот факт, что частота колебаний виртуального катода определяется эффективной плазменной частотой пучка.…”