强流相对论环形电子束自调制振荡研究

 主要研究了强流相对论环形电子束在等位谐振腔内的非线性自调制振荡，用小信号理论分析了电子起振的条件，得出了电子起振的扰动频率。基于该理论分析，又提出了一种不外加磁场的新型高功率微波器件，该器件主要由一个圆柱谐振腔和一个同轴波导输出腔构成。用2.5维MAGIC粒子模拟软件对该非线性过程进行数值模拟，分析了输入电压、电流对输出微波功率的影响。模拟结果表明这种结构中确实存在非线性不稳定性，自调制的扰动频率则由电子束的初始能量、电荷密度和电子束的半径以及谐振腔的空间结构给定。利用谐振腔长为4.7 cm、二极管电压为2.8 MV、电流为20 kA的电子束，可以得到频率为4.29 GHz、功率为6 GW的微波输出，束-波转换效率约为11%。

Self-modulation of intense relativistic annular electron beam in equipotential resonant cavity

This paper focuses on an intense relativistic annular electron beam in an equi-potential resonant cavity nonlinear self-modulation oscillation.By using the small signal theory,the start oscillation condition is analyzed and the perturbation frequency of the electron start oscillation is given.Based on this mechanism,a new type of high power microwave source is suggested with no additional magnetic field which is mainly made up of a cylinder cavity and a coaxial output cavity.PIC simulation of the nonlinear progress and the effect of input voltage and current on the output microwave power is carried out by using the 2.5-dimensional MAGIC code.The simulation results show that nonlinear instability truly exists in this configuration,the frequency of the self-modulation perturbation depends on the initialization of electron beam energy,charge density,electron beam radius and the size of the oscillation cavity.When the oscillation cavity is 4.7 cm long,the input voltage is 2.8 MV and the current of diode is 20 kA,a microwave pulse output power with a dominant frequency of 4.29 GHz,an average power of 6 GW is obtained.The efficiency is about 11%.