X 波段无导引磁场Cerenkov 型振荡器的仿真研究

利用2.5 维粒子模拟软件Karat 对一种无导引磁场X 波段Cerenkov 型高功率微波振荡器开展了仿真研究，利用冷腔色散曲线模型与Superfish 电磁场分布模拟软件选择了工作点，设计了基本模型。在基本模型的基础上进行仿真优化，通过采用内外约束阴极环提高电子束质量，采用锥变型收集极优化器件Q 值、增加模转效率、纯化输出微波模式，优化非均匀锥形慢波结构增强束波作用，最终使器件效率从17%优化到30%，输出功率达到1.8GW，输出微波模式为TEM模，频率9.1GHz,对应二极管工作电压620kV、电流9.4kA.

Simulation Investigation of an X-Band Cerenkov-Type Oscillatorwithout Guiding Magnetic Field

Through the 2.5D particle-in-cell simulation code Karat, an X-band Cerenkov-type oscillator without guidingmagnetic field is investigated by us. The operating frequency of the oscillator is determined by the cold cavity dispersion curvesand basic structure is built by the microwave distribution simulation software, Superfish . Based on the basic structure of theoscillator, the optimizations are worked by adopting the inner and outer constraining cathode circles to improve thetransportation quality of the electron beam, tapering the collector to optimize the Q-factor and purify the microwave mode, andoptimize the parameters of the nonuniform slow-wave-structure to enhance the beam-wave interaction. The efficiency of theoscillator is optimized to 30% from 15%, and the output wave power is 1.8GW with a frequency of 9.1GHz in the TEM mode.The corresponding diode voltage and beam current are 620kV and 9.4kA, respectively.