Research progress of Ka band Gyro-TWTs in IECAS

A high power Gyrotron Traveling-Wave Amplifier(Gyro-TWT) operating in the low-loss TE₀₁ mode has been designed and demonstrated. The gyro-TWT consists of a double-anode magnetron injection gun(MIG), TE₀₁ mode interaction circuit, a 36mm diameter collector, and a three disk sappire output window. A double-anode magnetron injection gun is designed to operate at 70 kV and 10A using the EGUN trajectory code and particle in cell program MAGIC. The electron beam with v_⊥/v_z =1.0 has a predicated axial velocity spread of 3-5%. The TE₀₁ mode interaction circuit is made up of a section of alternating metal and lossy ceramic (BeO+TiO₂) followed by a unloaded, metal-walled output region. The lossy property of the periodically loaded ceramic relieves the worries of the potential Bragg resonance arising from the periodicity of the interaction circuit, bring high attenuation to the potential competing mode, and enhances the stability of a gyro-TWT. The nonlinear self-consistent simulation code evaluated the operating characteristics of the gyro-TWT amplifier. For an axial velocity spread of Δv_z/v_z=3%, The predicted peak power is 180kW with -3dB bandwidths1.75GHz.