由激光靶冲量耦合实验结果判定激光支持爆轰波点燃阈值  

Determination of the Laser Supported Detonation Wave Ignition Threshold from Impulse Coupling between Laser and Target

作　　者：杨波[1] 朱金荣[1] 杨雁南[1] 沈中华[1] 陆建[1] 倪晓武[1] 

机构地区：[1]南京理工大学理学院

出　　处：《中国激光》2007年第1期139-144,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(60578015,60208004);博士点基金(20050288025);教育部高校优秀青年教师奖励计划资助项目。

摘　　要：根据激光吸收区等离子体组分与激光功率密度的关系判定激光支持爆轰波（LSDW）的点燃阈值。在激光靶冲量耦合实验的基础上,用悬摆动力学方程计算了激光支持爆轰波对铝靶冲量和冲量耦合系数;继而由靶冲量与激光吸收区膨胀介质（等离子体和气体）比热比的Jouguet条件,以及由二维流体动力学数值模拟获得的激光靶冲量随时间的变化过程,得到了激光吸收区介质的比热比随激光功率密度的变化情况,由此可得激光吸收区介质比热比随激光功率密度的增大而减少的结论;根据等离子体和气体比热比的差异定量分析了不同激光功率密度条件下激光吸收区气体和等离子体的构成。由等离子体含量随激光功率密度的变化关系得到了激光支持爆轰波的点燃阈值在（1.62±0.01）×10^8-（2.10±0.07）×10^8W/cm^2间的结果。The ignition threshold of laser supported detonation wave （LSDW） can be determined based on the component variation of plasma in the laser absorption zone with laser power density. A kinetic pendulum equation is presented for being adopted in the experiment of impulse coupling between laser supported detonation wave and aluminum target. Then considering the Jouguet relation between impulse and specific heat ratio of medium in the laser absorption zone （plasma and gas）, the relation between specific heat ratio and laser power density can be obtained for analyzing the result of two-dimensional hydrodynamic simulation. The specific heat ratio decreases while laser power density increasing. Finally, considering the difference between plasma and gas, the component of plasma and gas can be determined. The laser supported detonation ignition threshold is calculated in the space interval from （1.62±0.01）×10^8W/cm^2 to （2.10±0.07）×10^8W/cm^2. By comparing to the ignition threshold determined by the impulse-coupling coefficient, there is an ideal concordance in these two ways.

关 键 词：激光技术 激光与材料相互作用 激光支持爆轰波点燃阈值 Jouguet条件 激光吸收区 比热比 气体 等离子体 组分 

分 类 号：TN249[电子电信—物理电子学]