Nonlinear theory of relativistic microwave electron devices

The increase of output power is an important task of the theoretical and experimental research of resonant oscillators of millimeter and submillimeter waves (orotron, diffraction action radiation generator, laddertron, ledatron, etc.). It is well known that the application of relativistic voltages for acceleration of electron beams in millimeter wave oscillators allows to obtain high levels of output power of radiation. Dynamic relativistic variation of the electron mass can considerably change the character of the electron-wave interaction process. This effect is essential if the magnetic guide field strength is limited or DC focusing field is nonuniform. In this case the transverse electron-wave interaction and motion of electrons in the transverse direction should be taken into account, and for a theoretical description of the device a multi-dimensional model is applied