A new triplet gyrotron amplifier, the gyrotriotron

Summary form only given. A new triplet gyrotron amplifier, which we call gyrotriotron, has recently been developed. The device consists of a gyro-TWT input stage to modulate the beam at S₁=1 cyclotron harmonic, a four-unit clustered-cavity as intermediate stage to bunch the beam at S₂=2 cyclotron harmonic and a gyro-TWT output stage to extract energy from the bunched beam at S₃=2 cyclotron harmonic. Electronic coupling between neighboring stages is realized through ballistic beam bunching in the radiation-free drift space similar to what happens in a gyroklystron. Since S₃=S₂=2S₁, the device is a harmonic multiplying gyrotron amplifier with a scheme of 1-2-2. The clustered-cavity employed in the gyrotriotron is a group of TE₀₃ mode-selected cavities, which are closely adjacent and without any coupling between them. HFSS simulation of a sub-unit of such a mode selective clustered-cavity is given. This is a first use of cluster cavity in a gyrotron. The proof-of-principle gyrotriotron with Ku-band input, Ka-band TE₀₄ mode output, predicted peak output power of 500 kW and 5% bandwidth, has been fabricated and is being tested in the Harmonic Gyrotron Lab at University of Maryland.