Analysis of two-cavity gyroklystron

Abstract

Small signal analytical analysis and large signal numerical calculations are presented for a gyroklystron in which a low order (TE₀₁₁) mode in the bunching cavity is coupled by the electron beam to a high order (TE₀₄₁) mode in the output cavity. A drift region separates the two cavities. We demonstrate that the probunching of the beam before entering the output cavity not only enhances the interaction efficiency of the TE₀₄₁ mode but also improves the mode stability by suppressing the TE₂₄₁ mode. The gyroklystron may be operated either as an oscillator or as an amplifier by a small variation of the applied magnetic field. The effect of the beam velocity spread on the efficiency is also investigated. It is found that the operation of the gyroklystron is more sensitive to beam velocity spread than that of a gyromonotron. Optimum conditions for a cold beam are not necessarily those for a wam beam.