圆柱电极激光触发开关击穿前的模拟计算

在加入SF6气体与电子的碰撞反应截面后,利用基于PIC-MCC方法的XOOPIC程序,对天光Ⅰ号激光装置预放大器上的圆柱电极激光触发开关进行击穿前流柱形成过程的模拟计算。详述了模拟条件的选择及激光触发条件的等效,并给出了模拟结果。模拟结果表明,在弧道初始半径约为250μm的条件下,经过0.15 ns后正离子到达阴极,开关导通。因此验证了通过PIC-MCC方法模拟,可以为开关弧道的电阻的动态变化的电路模拟给出初始条件,使之能够更为准确的预测开关的导通行为,为开关设计提供了一个新的工具。

Simulation of laser triggered gas switch with cylindrical electrodes on pre-breakdown stage

The PIC-MCC simulation of a laser triggered gas switch (LTGS) with cylindrical electrodes has been conducted with XOOPIC code by adding electron-SF_6 collision cross section data. The LTGS works as the main switch of the pre-amplifier of Heaven-Light Ⅰ Laser generator. The paper presents the simulation results of the streamer formation on pre-breakdown stage of the gas switch, show that the initial radius of arc is 250 μm and the time at which the ions reach the cathode is about 0.15 ns. It also outlines the simulation conditions and some necessary assumptions and their effects on simulation results. The PIC-MCC simulation is intended to obtain the initial conditions needed by circuit simulation of the arc resistance and to predict the breakdown time of the gas switch. The simulation produces a novel design tool for estimating the dynamic behaviors of gas switch more accurately.