径向渡越时间振荡器的数值模拟

Numerical simulations of radial transit-time oscillator

用 2 .5维 PIC程序对径向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 ,得出了输出微波功率与提取口大小、腔的径向间距、场模式之间的关系。模拟得到了峰值功率约5 0 0 MW,频率 5 GHz的 TEM1波 ,起振时间 1 5 ns,峰值效率大于 30 %

Employing a 2.5-D PIC code, radial transit time oscillator, is simulated numerically and the details are presented. The relations between output power and extractor size, radial cavity span and different modes are obtained. The results indicate that with the extractor size decreasing from 1 cm to 2 mm, the output power increases, and the relation between radial cavity span and output power coincides with that derived from linear theory. Comparison of different modes shows that TEM1 is the most suitable mod e to generate high power microwave. With a 200 kV and 8 kA electron beam, A 500 MW, 5 GHz peak output power microwave with mode TEM1 is generated by simulation. The starting time to oscillate is less than 15 ns. The peak efficiency is over 30% .