大间隙C波段三轴速调管束流调制模拟研究

利用SUPERFISH软件设计了一种兼具大间隙速调管及三轴速调管优势的C波段大间隙三轴速调管，对所设计大间隙三轴速调管的束流传输及调制情况进行了2维粒子模拟研究。模拟结果表明，三轴速调管设计需要特别关注“模式泄露”问题以及谨慎选择内导体接地支撑杆的位置，以获得稳定传输的电子束。综合考虑上述两个条件，在440 kV的二极管电压下，5.0 GHz,200 MW的强注入功率可以获得11.8 kA的基频调制积分电流，束流调制深度88%，调制电流峰峰值大于40 kA，且调制电流具有良好的频率及相位稳定性。在此基础上，初步模拟得到了大于2.0 GW的平均微波功率，平均效率约33.8%。

Simulation study on beam current modulation of C-band wide-gap triaxial klystron

The wide-gap klystron and triaxial klystron are the recent developments of the conventional relativistic klystron amplifier, which can effectively improve the output power and efficiency especially at high frequency. The wide-gap triaxial klystron takes advantages of the two kinds of klystrons mentioned above. 2D particle-in-cell simulation on the electron beam transportation of the C-band wide-gap klystron is presented. In order to obtain stable beam transportation, both the radially asymmetrical cavity structure and cautious position choice of the grounding rod located before the input cavity are necessary. Under a diode voltage of 440 kV and an input power of 200 MW at 5.0 GHz, a maximum fundamental integral modulation current of 11.8 kA is obtained with the modulation depth of 88% and