Relativistic twistron based on backward-wave oscillator with modulating reflector and an efficiency of 56%

Technical Physics - Using numerical simulation, the operating mode of a relativistic Cherenkov microwave generator of the twistronic type has been demonstrated. The generator includes an...     

Relativistic X-band BWO with 3-GW output power

Results from a study of a relativistic X-band backward-wave oscillator (RBWO) with 3-GW output microwave power are presented. The RBWO was driven by the high-current electron accelerator SINUS-7. The dependence of radiated microwave pulse duration on microwave power was obtained. Pulse shortening occurring at the higher power levels is probably attributable to explosive electron emission from the slow wave structure (SWS). An increase in the cross section of the electrodynamic structure seems to be a way to increase the microwave pulse duration. Experimental results from a moderately oversized X-band RBWO using a resonance reflector are described. This tube can be operated with a low external magnetic field     

High-power relativistic microwave sources based on the backward wave oscillator with a modulating resonant reflector

Results of theoretical and experimental investigations into a relativistic backward wave oscillator with a modulating resonant reflector are generalized. The modulating resonant reflector is used to reflect a counter propagating wave and guide it toward an electron collector. It is shown that premodulation of the electron beam near the reflector may have a significant effect on the starting conditions of oscillation; selective properties of the oscillator; and its efficiency, which may reach 40% when a high-current beam is transported by a strong magnetic field. In the reduced magnetic fields that were employed in the pulsed-periodic regime and were 1.5–2.0 times lower than those at which cyclotron resonance with the counter propagating wave is observed, the oscillator efficiency (30–35% at a wavelength of 8 mm) is limited by position and velocity spreads of particles. Mechanical pulsewise frequency tuning within about 10% at a repetition rate of 1–50 Hz and a multigigawatt microwave power, as well as a rise in the power and energy of microwave pulses via an increase in the cross-sectional dimensions of the slow-wave structure, are demonstrated to be feasible.     

On Transient Time Reduction of a 2.4 GHz Relativistic Traveling Wave Oscillator with a Hollow Slow Wave System

The decrease in the transient time in a relativistic microwave traveling wave oscillator, in which the interaction is carried out between the relativistic electron beam and the fundamental harmonic of the forward-traveling electromagnetic wave slowed down to the speed of light in the hollow slow wave system system, has been numerically and experimentally demonstrated. It is shown that in this mode a high beam-to-wave coupling impedance up to ≈10 Ω is achieved, which ensures reduction of the transient time. In the experiment, a microwave peak power of 210 ± 30 MW at a frequency of 2.45 GHz in a guiding magnetic field of 0.16 T was obtained. The efficiency of the oscillator to convert the power of the electron beam into microwave power was 17 ± 3%. At the beam current pulse duration of about 50 ns the microwave pulse duration was about 20 ns and the transient time was about 22 ns.