The dynamics of multimode electronic masers

Energy and phase mode interactions in multimode masers are investigated. If the threshold of self-excitation in the oscillator is slightly exceeded and the modes in question have similar natural frequencies, then the principal nonlinear effect in the interaction between modes is their concurrence, which leads to the establishment of single-mode oscillations. When the beam current exceeds starting values by a larger amount, a mode with a low starting current, as a consequence of the dispersion of the nonlinearity of the electron flux, is able to support the oscillations of a mode of higher frequency; the increment of this high-frequency mode can be either positive or negative. Using a gyrotron as an example, it is shown that, as a result of this effect in an oscillator where there are three modes that differ considerably in frequency, the modes can be synchronized.