激光功率密度对纳秒激光烧蚀冲量耦合影响的数值模拟

Numerical Simulation of Laser Power Density Effect on Nanosecond Laser Ablation Impulse Coupling

关键词:  激光烧蚀  冲量耦合  激光功率密度  数值模拟  空间碎片 

Key words:  Laser ablation  Impulse coupling  Laser power density  Numerical simulation  Space debris

摘要:

为研究激光功率密度对纳秒激光烧蚀冲量耦合影响,建立了一个复杂的一维热传导和流体动力学模型。以空间碎片常见材料Al为例,用建立的物理模型数值计算了纳秒脉宽激光烧蚀产生的冲量随时间变化情况,数值结果和已有的实验数据符合较好。数值计算表明:辐照的激光功率密度越高,发生等离子体屏蔽时间越早,等离子体屏蔽越明显,能量利用率越低；随着激光功率密度的逐渐增大,获得的冲量逐渐趋于稳定,冲量耦合系数降低,数值计算结果与Phipps的最优能量耦合规律一致。 

Abstract:

To investigate the effects of different laser power density on impulse generation of laser ablation target, a comprehensive model including one-dimensional heat conduct and fluid dynamics was developed. The target Al, the most common space debris material, was used based on the built numerical model in the calculation of nanosecond laser ablation impulse as a function of time. The numerical results agree well with experimental data available. Numerical simulations show that, the higher the laser power density is, the earlier the plasma shielding will turn up and the more obvious the plasma shielding effect will be. This may lead to a lower energy utilization. With the increase of laser power density, the gained impulse tends to be stabe and the impulse coupling coefficient decreases. The results are consistent with the optimum energy coupling theory derived by Phipps. 