阴极内嵌绝缘子对真空中平行双丝电爆炸的影响

Influence of Insulated Cathode on Electric Explosion of Parallel Double Wire in Vacuum

真空中金属丝阵电爆炸存在极性效应,改变丝表面径向电场的方向和大小会影响金属丝阵电爆炸过程中的沉积能量。为此使用阴极内嵌绝缘子的方法改善平行双丝负载的径向电场分布,以提高平行双丝负载的沉积能量,并将其与普通电极构型进行对比。先利用COMSOL软件对2种电极结构分别进行仿真计算,结果表明:阴极内嵌绝缘子的方法可以有效改善平行双钨丝负载表面的径向电场分布,将负方向的径向电场转变为正向的径向电场,从而可有效抑制金属丝表面的电子发射。PPG-3装置的实验结果进一步验证了上述结论:阴极内嵌绝缘子的电极构型可以显著提高金属丝阵中的沉积能量(每原子平均沉积能量由3.2 eV提升至12.5 eV),并使爆炸丝具有更高的膨胀速度(1.23 km/s增加至3.95 km/s)和汽化比率。

The polarity effect exists in the electrical explosion of wires(EEW)in vacuum.Changing the direction and value of the radial electric field can change the deposition energy of EEW.Consequently,we adopted an insulated cathode(cathode with an embedded insulator)to improve the distribution of surface radial electric field of parallel double-wire load.In order to verify the effectiveness of this method to improve the deposition energy of EEW,we carried out simulation of electrostatic field under two types of electrodes(an insulated cathode and a normal cathode).Simulation results show that the insulated cathode can effectively improve the distribution of radial electric field on the surface of parallel wires:changing the negative direction of radial electric field into positive direction,thus suppressing the electron emission of wire surface.The experimental results based on a PPG–3 device further verify the conclusion that the insulated cathode can significantly improve the deposition energy in wires(from 3.2 eV to 12.5 eV)and result in a better electric explosion effect with a faster expansion rate(from 1.23 eV to 3.95 eV)and higher vaporization ratio.