针对大气中飞行器的等离子体隐身问题,数值计算了ns量级强激光击穿大气的阈值,讨论了一些相关条件对阈值的影响.结果表明:对于ns量级的入射激光,波长越长,大气的击穿阈值越小;气压越大,击穿阈值也越小;气体中存在的初始电子对不易产生光电离的长波长入射激光的击穿阈值,有明显的减少作用,但对短波长入射激光的击穿阈值几乎没有影响;脉宽越宽,激光辐照的时间越长,大气击穿的阈值越小.

In order to get the plasma in air for aircraft stealth,this paper calculates the breakdown threshold of atmosphere from semi-classic theory.The main subjects include the connection between the breakdown threshold and atmosphere pressure,and the connection between the breakdown threshold and laser duration.At the same time,the paper has a keen study on the breakdown time of different laser intensity.Besides,the discussion on the effect of initial electron in air is also included in all above analysis,the data indicate that under the influence of the electron,the threshold for long wavelength incident laser falls distinctly,but there is not any change for short wavelength laser(0.355 μm).