多间隙耦合腔中注-波同步与耦合

Beam-wave synchronization and coupling in a multi-gap coupled cavity

本文基于空间电荷波理论,导出了N间隙耦合腔中注-波耦合系数和电子注电导计算公式.通过计算分析多间隙耦合腔中工作模式(2π模)耦合系数和归一化电子注电导随间隙数目N、直流电压和导流系数的变化,研究多间隙耦合腔中注-波耦合和同步关系,对分布互作用速调管的理论研究有指导意义.

The analytical expressions of the beam-wave coupling coefficients and the beam-loaded conductance in an N-gap coupled cavity are derived based on space-charge wave theory.Through calculating the relations of the beam-wave coupling coefficient and the normalized beam-loaded conductance to the gap number,beam voltage and perveance for 2π mode,the mechanism of the beam-wave synchronization and coupling in the multi-gap coupled cavity are discussed.The results show that,with the increase of N（≥2）,the beam-wave coupling efficiency and the normalized beam-loaded conductance vary with beam voltage more rapidly and there is a maximum value for the absolute squared value of the coupling coefficient ｜ MN ｜ 2 and a maximum value and a minimum value for the normalized beam-loaded conductance gb.The magnitudes of these extrema increase with the increase of gap number N,and the corresponding voltage is close to the synchronization voltage.The increase of the perveance could make the voltage difference between two extremums of gb increase,the magnitudes of these extrema decrease,and the beam-wave coupling efficiency fall.