TE11模式增强型高效率同轴虚阴极振荡器

 在阴阳极严格同轴的条件下，理论分析表明同轴虚阴极振荡器中TE₁₁模式与TM₀₁模式与径向入射电子束的谐振耦合具有近似的作用效率。3维PIC数值模拟结果显示，即使在圆对称结构下，输出波导中非角向均匀模式在输出功率中也占有较大成分。因此，同轴虚阴极振荡器中TE11模式与电子束之间的谐振作用对器件效率的影响不可忽略。通过引入结构的不对称性以及TE11模式反射器可以抑制电子束与TM₀₁模式之间的谐振作用，从而起到抑制同轴虚阴极振荡器系统中模式竞争的作用，因此可以提高电子束到微波的功率转换效率。实验结果表明，采用阴阳极非均匀对称结构的TE₁₁模式增强型同轴虚阴极振荡器可以大幅度提高效率，在优化参数条件下获得功率转换效率约7％，输出功率大于1.0 GW的实验结果，该功率约为近似严格同轴结构的2.5倍。该研究结果可以为高效率同轴虚阴极振荡器装置设计与实验结果分析提供基本理论依据以及参数确定基础。

High efficient TE11 mode enhanced coaxial vircator

Coupling efficiencies of TE_(11) and TM_(01) modes oscillating with radial injected electron beam in coaxial vircator present nearly the same value for coaxial geometry.3D PIC simulation result shows that non-poloidal uniform mode dominates the output power.The effect of TE_(11) mode oscillating with injected electron beam on the performance of coaxial vircator can not be ignored.By introducing an unsymmetrical geometry and a TE_(11) mode reflector,the coupling efficiency between electron beam and TM_(01) mode is restrained.Consequently,the modes competition in the beam-EM wave interaction cavity is quenched,which leads to the increase of the energy conversion efficiency.The TE_(11) mode enhanced coaxial vircator with a non-coaxial geometry gives the power efficiency of 7% and 1.0 GW output power in the experiment,which is approximately 3 times of the coaxial geometry.