基于粒子模拟技术研究了螺旋线行波管的时域非线性理论,慢波结构中的场通过螺旋带模型求解得到,并考虑了夹持杆和屏蔽桶的影响,推导得到了注-波互作用的动理学方程;聚焦磁场可以是直流磁场也可以是周期永磁场;用泊松方程求解得到空间电荷场;注-波互作用方程用MacCormack的差分格式进行计算。给出了时域计算得到的瞬态特性,并与基于一维Christine及三维Christine理论的计算结果进行了比较。
The nonlinear theory of helix traveling wave tube (TWT) was developed,based on the particle simulation in time domain.The wave propagating through the helix was modeled with a configuration consisting of the three-dimensional helix belt,the dielectric rod load,and conducting walls.In the derivation,either a uniform field generated by a solenoid or a periodic field produced by a permanent magnet stack,were used to focus the electron beam;and the electric field induced by electron beam was evaluated with Poisson equation on the basis of finite-difference grid formulation.The interaction between the electron beam and the wave was calculated in MacCormack difference method.The time varying output of the helix TWT was calculated.The simulated results were compared with those obtained by Magic simulation code and three-dimensional Christine code.