Nonstationary phenomena in a gyrotron operating in the presence of reflections

The output signal of mismatched gyrotrons constitutes a superposition of periodic and/or quasiperiodic oscillations with a finite number of fundamental frequencies which are related to the eigenfrequencies of the mismatched cavity. The gyrotron behavior is regular. For high reflection coefficients, the main mode as well as most of the other modes of the mismatched cavity are suppressed by that mode which shows the highest eigenfrequency and whose field profile shows its maximum in the vicinity of the left aperture.