相对论返波管中的脉冲缩短现象

 脉冲缩短现象是高功率微波器件中普遍存在的物理现象，它将导致输出微波的能量低于预期值。用粒子模拟的方法研究了相对论返波管在填充氦气以及存在中性背景气体时的脉冲缩短现象。从计算结果可以看出，器件内残留的中性背景气体是产生脉冲缩短的原因之一，但并不是最重要的因素；对于充气的相对论返波管，为了展宽脉宽，充气气压必须控制在一个适当的水平。器件内部强电场的射频击穿和慢波系统表面的爆炸发射可能是引起脉冲缩短的更为重要的因素。

Pulse shortening phenomena in relativistic backward wave oscillator

In this paper, the pulse shortening phenomena in relativistic backward wave oscillator(RBWO) are studied by means of the particle-in-cell method under two conditions of filling He gas or remaining background gas in the tube. The calculation results predict that the background gas in the tube is one but not the most important factor resulting in pulse shortening, and in order to broaden the pulse width of the gas-filled RBWO, the pressure of the filled gas must be controlled in a proper value. The intense electric field RF breakdown inside the tube and gas molecule explosive emission on inner surface of the slow wave system may be more important factors resulting in the pulse shortening phenomena in the high power microwave tube.