等离子体填充波纹波导中低频模式特性分析

采用等离子体流体模型和线性场理论，导出了在强引导磁场下，一无限薄环形等离子体加载 波纹波导中电磁波传播的色散关系.数值计算并分析了在不同的等离子体填充密度下，低频 等离子体模式的色散特性和行波管的小信号增益.研究发现，低频等离子体模式可与相对论 电子束发生同步互作用使高频信号放大.同时，在无限薄环形等离子体填充条件下，波纹波 导中的低频等离子体模式严格满足Floquet定理所要求的周期性，其上截止频率不再受到等 离子体频率的限制，当密度较大时，等离子体模式还可与TM模式发生耦合. 关键词： 等离子体 波纹波导 色散关系 增益

Analysis of the characteristics of low-frequency modes in a corrugated waveguide filled with plasma

A corrugated waveguide filled with an infinitely thin annular plasma is immersed in a strong longitudinal magnetic field. By means of fluid model and linear field theory,the dispersion relation of the electromagnetic wave propagation along the system is derived. The dispersion characteristics and beam wave interactions of low frequency plasma modes are analyzed in two cases of various densities of plasma by numerical computation. It is found that the dispersion relation without electron beam satisfies exactly the Floquet theorem and the frequency of electromagnetic wave could not be confined by plasma oscillation frequency. The low frequency plasma modes can even be coupled with TM modes as the plasma density is increased.