A ring-shaped travelling-wave open resonator as part of the diffraction radiation oscillator

The diffraction radiation oscillator (DRO) operates upon the effect of diffraction radiation (DR) arising, when an electron beam skims the diffraction grating installed in the open resonator (OR). The examination of the fine structure of the diffraction radiation has revealed channels through which a noticeable part of the energy is carried off rather than being transformed to the OR natural field. This fact keeps us in a search for new OR designs that are able to accumulate the diffraction radiation with a wide angular spectrum. This work contributes to the research into a travelling-wave open resonator (TWOR) as a DRO part. It is the TWOR that shows real promise as an open resonant system capable of retaining in its volume the diffraction radiation with a wide angular spectrum. In addition, this OR design, with a Gaussian beam moving round a circle for gains in the loaded Q, makes it possible to select the excited oscillations in the DR direction and to output the diffraction energy to the load easily enough.