Ultramicrowave Electron-Beam Tubes.

The paper gives an overview of the physical and technical aspects of the generation of millimetric waves with the aid of relativistic electron beams. First, the interaction between electron and electromagnetic RF fields is treated in general, and the excitation condition for coherent radiation is discussed in consideration of dispersion relations. This is followed by a discussion of electron-ray tubes, whose working principle is based on the interaction between electrons and 'slow' electromagnetic waves. In this context, mention is made of the Cerenkov and Smith-Purcell radiation as well as special ultramicrowave tubes (Orotron, Ledatron).