空气光学击穿的光线追踪模型  

A ray-tracing model of air optical breakdown

作　　者：黄辉[1] 洪延姬[1] 李倩[1] 曹正蕊[2] 冯海兵[2] 

机构地区：[1]装备指挥技术学院基础部,北京101416 [2]装备指挥技术学院研究生院,北京101416

出　　处：《爆炸与冲击》2010年第2期209-214,共6页Explosion and Shock Waves

基　　金：国家自然科学基金项目(10672184)~~

摘　　要：为了探讨激光与物质的相互作用规律,利用光线追踪法,建立了一种空气光学击穿模型,根据光线在网格中的传播路径信息,运用辐射输运方程,得到流场的功率密度分布,模拟了空气的光学击穿过程。针对透镜聚焦情形,使用不同的计算网格和光路对模型进行了验证,计算得到的空气击穿等离子体流场爆轰波的形成和演化过程,与实验结果基本一致。结果表明:当焦平面处的艾里斑半径比该处网格尺寸大得多时,模型对计算网格的依赖性比较小;击穿区域的温度必须高于14000K,否则不能沉积能量。By using the ray-tracing method, an air optical breakdown model was proposed for investigating the laser-material interaction. The laser beam was divided into a number of rays, which were tracked to compute radiation intensity by the radiation transfer equation, and the air optical breakdown was simulated. In the lens focusing system, different grids and ray paths were used to validate the proposed model, and good agreement was achieved between numerical and experimental results for the laser-induced air plasma field. It is indicated that the model depends little on the computational grids when the radius of the Airy disk is much larger than the size of the grid around the focus point, and that the temperature in the breakdown region must be higher than 14 000 K, otherwise the laser energy can not be deposited.

关 键 词：爆炸力学 光学击穿 光线追踪法 能量沉积 艾里斑 

分 类 号：O381[理学—流体力学]