RAPID FREQUENCY STEP-SWITCHING OF A SUBMILLIMETER-WAVE GYROTRON BY MODULATION OF THE ELECTRON-BEAM

An experimental study of the rapid step-switching of the frequency of a submillimeter wave gyrotron is described. Modulation of the energy of the electron beam in tum modulates the electron mass and hence the cyclotron resonance frequency f(c) or its second harmonic 2f(c), while the magnetic field B0 remains the same. This opens up the possibility of switching from one cavity mode to another. The first experimental results for frequency switching between two fundamental modes and between a fundamental and a second harmonic mode are demonstrated.