第 42 卷 第 9 期
2015 年 9 月
Vol. 42, No. 9
September, 2015
中 国 激 光
CHINESE JOURNAL OF LASERS
0902001-
强激光水中诱导等离子体冲击波数值模拟
鲁建英
1
耿德珅
2
陈 朗
2
1
中国人民解放军防化学院, 北京 102205
2
北京理工大学爆炸科学与技术国家重点实验室, 北京 100081
摘要 在强激光与水介质作用过程中 ,等离子体和冲击波的形成机理 是人们 关心的主要问题之一。采用双脉冲激
光纹影摄影法,获得了强激光作用时水中的冲击波流场图形,建立了激光与水作用两相流计算模型,建模时考虑了
激光吸收,水体汽化、等离子体形成和膨胀等过程。对强激光作用水体形成冲击波的过程进行了数值模拟计算,获
得了与实验相符的计算结果。进一步分析了激光诱导等离子体冲击波的传播特性,并与经典理论模型结果进行了
比较。研究结果表明,在激光作用下,水中等离子体快速膨胀形成的冲击波传播初始速度高达上千米每秒,压力约
为十几吉帕,随后冲击波的速度和压力迅速衰减,1 ms 后衰减到声波速度。
关键词 激光技术; 冲击波; 数值模拟; 水
中图分类号 O383 文献标识码 A
doi: 10.3788/LOP42.0902001
Numerical Simulation of High Intensity of Laser Induced
Plasma Shock Wave in Water
Lu Jianying Geng Desheng Chen Lang
1
Institute of Chemical Defense, Chinese People′s Liberation Army, Beijing 102205, China
2
State Key Laboratory of Explosion Science and Technology, Beijing Institute of Technology, Beijing 100081, China
Abstract Laser-induced plasma formation and shock wave generation mechanism are our concern problems in
investigating high intensity laser pulse focusing into water. A high speed schlieren photography technique with
double-pulse lasers is used as a background light source, and the temporal and spatial evolution of shock wave
are obtained. A two- phase computation model is established in consideration of water vaporization, plasma
absorption laser pulse energy. The processes of laser induced plasma shock wave in water are numerically
simulated. A reasonable agreement is obtained between experimental and simulation results. The shock wave
propagation characteristics are studied,and comparison between simulation results and theoretical predictions
are presented. The results show that the shock wave speeds in the initial stages of laser induced breakdown in water
is up to 5 km/s, and pressure is up to a dozen GPa. Shock wave velocity and pressure decay rapidly over time, which
decrease to acoustic speed in an 1 ms later after breakdown.
Key words laser technique; shock wave; numerical simulation; water
OCIS codes 140.3440; 350.3390; 350.5400
收稿日期: 2015-03-20; 收到修改稿日期: 2015-04-21
基金项目: 国家自然科学基金(11302251)
作者简介: 鲁建英(1975—),女,博士,讲师,主要从事激光与物质相互作用等方面的研究。E-mail: fhxyljy@sohu.com
1 引 言
强激光击穿水介质发生电离,产生高温高压等离子体,等离子体向外膨胀过程中形成冲击波,同时在水
中形成空泡,该现象可 以用于激光推进
[1]
、声波探测
[2-3]
和眼科手术
[4]
等多个研究领域。考 察激光作用时水中
等离子体和冲击波的形成机理和作用规律,建立相应理论计算方法是人们需要关心的问题。美国 Felix 等
[5]
采用纹 影摄像方法 ,观测了激光 聚焦于 水、甲 醇等液体中 的冲击 波。Jean 等
[6]
采用压 力传感器,测 量了激光
作用下水中冲击波压力,给出了冲击波速度与激光能量的关系。Joachim
[7]
研究了激光脉冲宽度对水中 冲击
1