High power microwave generation in virtual cathode systems

There are two mechanisms which lead to production of high-power microwaves in vircators. The first deals with electrons oscillating near the anode and the second with the virtual cathode (VC) oscillating as a whole. Generally, both mechanisms are present, but in a given device one may dominate the other. If the anode is thick enough to absorb reflected electrons, thus preventing them from reentering the diode region, the first mechanism vanishes. A discussion is presented of the second mechanism, which is realized, for example, in the reditron. Anode plasma produced by high-current electron beam passing through the anode is taken into account. Based on their experimental work, the authors conclude that the vircator is a source of powerful microwave oscillation not only of centimeter but also millimeter and sub-millimeter ranges.<>