具有分布损耗波导结构的回旋行波放大器绝对不稳定性

详细推导了具有分布损耗波导结构的回旋行波放大器的色散特性。通过绝对不稳定性振荡出现的条件，给出求解具有损耗波导结构回旋行波管放大器的绝对不稳定性起振电流的数值计算方法。研究结果表明：绝对不稳定性起振电流与损耗波导的集肤深度有关，选择有较大的集肤深度的损耗波导可以提高绝对不稳定性起振电流；绝对不稳定性起振电流同时也与工作磁场偏离饱和磁场的程度以及电子束的纵横速度比有关；通过设计具有分布损耗波导结构的注-波互作用电路，以及工作磁场、电子束的纵横速度比，可以在兼顾带宽、效率的条件下，保证回旋行波管放大器稳定工作。

Absolute instability in gyrotron traveling wave amplifier with distributed loss waveguide

This paper presents a quantitative study of the critical current above which absolute instability would be excited in gyrotron traveling wave amplifier with the distributed loss waveguide. The dispersion property of a distributed-loss waveguide is derived in detail. The numerical results show that the threshold current depends on the skin depth of the waveguide wall, the magnetic field detuning and the perpendicular-to-parallel velocity ratio of the electrons. By designing the beam-wave interaction circuit with distributed-loss waveguide, the applied magnetic field and the velocity ratio, stable operation of the gyrotron traveling amplifier with wide band width and high efficiency can be ensured.