Radiative Pierce instability in plasma waveguides

The majority of present-day high-power pulsed microwave sources are based on the resonant stimulated emission of microwaves by relativistic electron beams in various electromagnetic systems. One of these sources is the relativistic Cherenkov plasma microwave oscillator. However, the system able to confine the plasma for a long time is expensive. Alternative devices, nonresonant microwave oscillators based on the radiative Pierce instability are considered. Radiative Pierce instability develops in systems in which strong positive feedback occurs. This feature makes Pierce instability universal, unlike resonance instabilities (such as Cherenkov). The same feature does not allow the creation of amplifiers working with this effect, but allows a wide class of oscillators to be created. In plasma waveguides we can select at least three regimes of Pierce instability. If in the system the feedback is effected by beam potential wave then aperiodic instability occurs, which breaks beam current and doesn´t produce radiation. Radiative instability arises if the feedback is affected by non-potential wave