Controlling the frequency of periodic self-modulation in gyrotrons with external reflections

We develop the theory of electron–wave interaction in gyrotrons with reflections part radiation, focusing on implementation self-modulation generation regimes controlled frequencies. The optimal conditions for simultaneous excitation neighboring axial modes electrodynamic system a gyrotron reflecting diaphragm output waveguide path are found. When is powered by an electron beam under these conditions, periodic realized distance between main spectral components varying to reflector. conclusions confirmed results direct particle-in-cells simulation.