X波段内同轴膜片加载相对论返波振荡器的特性研究

 把同轴膜片作为相对论返波振荡器的慢波结构，从Maxwell方程组和Floquet定理出发，导出了电磁波在同轴膜片加载相对论返波振荡器中的色散关系。通过编程计算得出TM_0n模式的色散曲线，数值分析了周期长度和导体半径对器件工作频率的影响，运用PIC程序模拟了返波振荡器中注波互作用过程。讨论了纵向聚焦磁场、电子注到慢波结构的距离、槽深和槽宽对输出功率和效率的影响。研究表明：增加器件的周期长度，可以减小器件的截止频率和同一模式下的工作频率； 调节内导体半径的大小，几乎不影响器件的工作频率。周期长度取11 mm，槽深取2 mm，槽宽取3.6 mm，漂移长度取7.5 mm的结构，在520 kV电压、8 kA电流和0.7 T的轴向聚焦磁场条件下，器件能输出2.8 GW的峰值功率,功率效率约33.2%。该慢波结构加工方便，具有广阔的应用前景。

Research on X-band inner coaxial disk-loaded relativistic backward-wave oscillator

The relativistic backward-wave oscillator(RBWO) with inner coaxial disk-loaded slow-wave structure(SWS) is studied.The dispersion relation of the SWS is deduced by using the Borgnis's potential function method according to Maxwell's equation and Floquet theory.Numerical analysis is carried out and the dispersion curves are gotten.The beam-wave interaction of the device is simulated and optimized by PIC method.The effect of the longitudinal magnetic field,the distance r_1 between beam and SWS,the depth r_2 of loaded-disk and the distance of two next disks are discussed in detail.The results show that increasing the periodic length can decrease the cut-off frequency and the operating frequency of the same mode and that the variation of the inner conductor radius almost has no effect on the operating frequency of RBWO.When the longitudinal magnetic field is 0.7 T,the periodic length 11 mm,the r_1 and r_2 are 2 mm,and the distance of two next disks is 3.6 mm,the peak output power and efficiency would be higher than 2.8 GW and 33.2% driven by 520 kV,8 kA electron beam with a suitable drift-tube in the SWS.