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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)×108~(2.10±0.07)×108W/cm2间的结果。
The ignition threshold of laser supported detonation wave (LSDW) is determined according to the relationship between the laser absorption zone plasma composition and laser power density. Based on the experiment of laser target impulse coupling, the impulse and momentum coupling coefficient of laser-supported detonation wave to aluminum target was calculated by the dangling dynamics equation. Then, the ratio of target impulse to the ratio of specific heat of expansion medium (plasma and gas) Jouguet condition and the change of laser target impulse with time obtained by two-dimensional numerical simulation of fluid dynamics, the change of specific heat ratio of laser absorption medium with the laser power density was obtained, and the laser absorption medium The specific heat ratio decreases with the increase of laser power density. The composition of gas and plasma in laser absorption region under different laser power densities is quantitatively analyzed according to the difference of specific heat ratio of plasma and gas. The ignition threshold of the laser - supported detonation wave was obtained in the range of (1.62 ± 0.01) × 108 ~ (2.10 ± 0.07) × 108W / cm2 from the relationship between plasma content and laser power density.