Enhancement of superradiance using modified intense relativistic electron beams

电子束受激辐射-超辐射(SR)是产生超短电磁脉冲的一种很有吸引力的方法。在这里，我们进行了S波段的超辐射实验。利用切伦科夫机制，利用短电子束在波纹波导中运动，获得了S波段最有效的SR脉冲。而S波段的长波使使用脉冲宽度为10 ns的强流相对论电子束成为可能。在实验中，用600keV、5kA的强流相对论电子束注入波纹波导，获得了5 GHz、300 mW、脉宽5 ns的微波。在SR中观察到的辐射模式为TM01。PIC模拟表明，辐射是由超辐射引起的。用同轴腔修正了电子束能量波形的时间演化。改进后的能量波形使SR的输出功率提高了20%。可以通过改变强流电子束的能量波形来增加超辐射的输出功率。

Stimulated emission from electron bunches - superradiance(SR) is an attractive method of generating ultrashort electromagnetic pulses. Here, we carried out the experiments on S-band superradiance. The most effective generation of SR pulses at S-band is obtained by Cherenkov mechanism with short electron beam moving in corrugated waveguide. And the long wavelength in S-band makes it possible to employ an intense relativistic electron beam with pulse duration of 10 ns. In the experiment, 5 GHz, 300 MW microwave with duration of 5 ns was obtained using a 600 keV, 5 kA intense relativistic electron beam with duration of 12 ns injected into the corrugated waveguide. The radiation mode was observed to be TM01 as expected in SR. PIC simulation indicated that the radiation was caused by superradiance. A coaxial cavity was used to modify the time evolution of the energy waveform of an electron beam. The output power of SR was 20% increased using the modified energy waveform. It could be possible to increase the output power of superradiance by modifying the energy waveform of an intense electron beam.