用2.5维PIC程序对三腔渡越时间振荡器进行了数值模拟,给出了产生微波的详细物理图像.模拟表明:三腔渡越时间振荡器能调制强流电子束并输出微波,微波频率符合理论设计值.模拟得到了输出微波功率随栅网间距,随反向二极管轴向间距以及提取口径向间距变化的规律.输出微波功率与栅网间距的关系与线性理论基本相符.在电子束电压400kV,电流4kA的条件下,模拟得到的结果为微波峰值功率约600MW,频率5GHz,起振时间约3.5ns,峰值功率效率大于37%.

By employing a 2.5-D PIC code, the three-cavity transit-time oscillator (TCO) was simulated numerically. It was found that the TCO can modulate REB, the modulated beam can be converted to HPM, and the frequency of microwave accords with the theoretical value. The relation between output power and span of inverse diode and that between output power and r-distance of extractor were obtained. The relation between output power and span of foils accords with that of the linear theory. A 600 MW, 5 GHz peak output power microwave is generated by simulation, with 400 kV electron beam voltage and 4 kA current. The start time to oscillate is about 3.5 ns. The peak efficiency is over 37%.