同轴相对论返波管中波束作用过程

根据同轴相对论返波管的特点建立了物理模型，采用时域有限差分法研究了同轴相对论返波管中波束作用过程。研究表明:同轴相对论返波管中波束作用的输出效率与两端反射系数密切相关，而且其内部场分布特点对于提高输出效率非常有利。经过优化设计，利用 500 keV, 4.0 kA 电子束流，微波起振时间为7 ns，输出效率大于38%，与以往数值模拟和实验结果符合较好。根据计算结果进一步分析得到，与空心相对论返波管相比，同轴相对论返波管中空间电荷效应的影响较小。

Wave-beam interaction in coaxial relativistic backward wave oscillator

The physical model is established according to the characteristics of coaxial relativistic backward wave oscillator(CRBWO) to study the wave-beam interaction in CRBWO employing the finite-difference time-domain method. The research indicates that the output efficiency of the wave-beam interaction in CRBWO is sensitively dependent on the reflections on both ends of the wave-beam interaction region. And the distribution of the field in CRBWO is beneficial for the promotion of the output efficiency. In the case of electron beam of 500 keV and 4.0 kA, the calculated output efficiency more than 38% through optimizing and the starting time 7 ns agree with those obtained from previous numerical simulation and experiment results very well. The space charge effect can be considered as a small influence on the wave-beam interaction in CRBWO compared with that in hollow relativistic backward wave oscillator.