Generation of high-power ultrashort electromagnetic pulses on the basis of effects of superradiance of electron bunches

Abstract

One of the promising methods for generation of ultrashort electromagnetic pulses (with duration of about ten periods of high-frequency oscillations) is radiation from spatially localized electron ensembles (bunches), which can be considered a classical analog of Dicke superradiance known in quantum electronics. In classical electronics, superradiance can be related to various mechanisms of stimulated radiation. Until now, cyclotron, undulator, andČerenkov (in the case of interaction with both copropagating and counterpropagating waves) superradiance of electron bunches as well as superradiance during stimulated scattering of a pump wave have been studied theoretically and experimentally. As a result of these studies based on high-current RADAN and SINUS accelerators and their modifications, a new class of oscillators producing pulsed electromagnetic radiation has been created. They have such unique characteristics as pulses of high peak power (up to 1 GW and 3 GW in the millimeter-and centimeter-wave ranges, respectively) and ultrashort duration (from 300 ps to 1 ns, respectively). In this case, regimes with a peak radiation power exceeding the electron-beam power are experimentally realized. Regimes with high (kilohertz) pulse repetition rate and high average power (up to 2.5 kW) are obtained.

Experiments Designed to Study the Non-Linear Transition of High-Power Microwaves through Plasmas and Gases

“…An SR-BWO (Super Radiance Backward Wave Oscillator) [28][29][30][31][32][33] can generate hundreds of MegaWatt (MW) to a few GW peak power in sub-ns pulses. An SR-BWO has an extended length SWS (Slow Wave Structure) compared to a conventional BWO, along which the beam self-bunches and interacts coherently with a slow spatial harmonic of the electromagnetic wave producing a short single radiation pulse.…”

High power microwave source for a plasma wakefield experiment

“…For the case of microwave pulse duration 1 ns, the most suitable and compact HPM source for the research of wakefield generation is a superradiance backward wave oscillator (SR-BWO), which can generate from hundreds of MW to a few GW of peak power. [19][20][21][22][23] The most important difference between the SR-BWO and the long-pulse relativistic BWO is an extended length of the slow-wave structure (SWS). The coherence of the emission into a short single pulse is caused by selfbunching of the electron beam, which interacts with a slow spatial harmonic of the electromagnetic wave.…”

“…21,22 Using this approach, microwave pulses with central frequency, f % 9:3 GHz; peak power P % 3 GW, and full width half maximum (FWHM) duration s mw % 650 ps were obtained. 23 In this paper, we describe the development of a SR-BWO microwave source, generating a 9.6 GHz Gaussian microwave beam, with a peak power up to $550 MW and a duration (FWHM) of $0.5 ns. The microwave beam is focused using a dielectric lens onto a spot radius of $2 cm, where the interaction of the beam with plasma will be investigated.…”