高功率回旋振荡管Denisov型辐射器的研究

Stady on a high efficient Denisov-type launcher for high-power gyrotron oscillators

研究了一种用于高功率回旋振荡管准光模式变换系统的高效率Denisov型辐射器.基于Bessel函数的积分展开及几何光学理论,系统地分析了圆波导中电磁波的传播过程及Denisov型辐射器降低衍射损耗的机理;分析了在圆波导内壁上工作模式与耦合模式叠加形成准高斯型场分布的过程.从Bessel函数导数的本征值出发,给出了不同工作模式在Denisov型辐射器预聚束波导段选择目标耦合模式的一种普适方法,同时给出了Denisov型辐射器的设计方法.依据上述理论分析编写了计算程序,并对一支140 GHz,工作模式为TE28,8,1 MW长脉冲回旋振荡管进行了对比验证,计算结果与文献报道的结果具有很好的一致性.

In this paper, a high-efficiency Denisov-type launcher, a hardcore of quasi-optical mode converters in high-power gyrotron oscillators, is investigated. Based on integral expression of Bessel functions and geometric optics, the propagation of EM wave in circular waveguides, the syntheses of amplitude and phase of nine modes are analyzed in detail. A generalized method for designing the launcher with a dimpled waveguide wall operating in different modes is demonstrated. This method shows how to select a set of appropriate coupled modes to synthesize the Gaussian-like distribution on the inner wall of the launcher. A program is developed and its accuracy is confirmed by a high-power gyrotron at 140 GHz, in TE28,8 mode theoretically. Numerical calculations show a good agreement with reported results.