Effect of ambient pressure on laser ablation and plume expansion dynamics: A numerical simulation
Effect of ambient pressure on laser ablation and plume expansion dynamics: A numerical simulation
复制标题
DOI：
10.1063/1.2182078
复制
发表时间：
2006-03-15
影响因子：
3.2
通讯作者：
Bogaerts, A
中科院分区：
文献类型：
--
作者：
Chen, ZY;Bleiner, D;Bogaerts, A
应用一个综合的数值模型研究了激光烧蚀过程中环境压力对铜靶加热、熔化和汽化的影响，特别是对氦气中羽流膨胀的影响，以及羽流中等离子体的形成。在研究的激光脉冲条件下[5 ns半最大全宽，10(9)W/cm(2)峰值辐照度]，计算结果表明，即使环境压力变化很大，表面温度和蒸发深度的特征也非常相似。环境压力对吸收激光能量的影响也很小。羽流中最大烧蚀物质蒸汽密度受不同压力的影响较小。在40ns之前，不同环境压力下羽流温度的最大值在10(4)k左右，但环境压力对羽流长度的影响相当大。对6 ns FWHM、峰值辐照度为2.76x10(9) W/cm(2)的高斯型激光脉冲进行了具体计算。计算的蒸发深度与实验数据吻合较好。因此，该模型可用于预测目标和羽流（等离子体）特性的变化趋势，而这些特征在不同环境压力下很难通过实验获得。(c) 2006年美国物理研究所。
A comprehensive numerical model is applied to the study of the effect of ambient pressure in laser ablation, more specifically on the copper target heating, melting and vaporization, and the resulting plume expansion in the helium gas, as well as on plasma formation in the plume. Under the laser pulse condition investigated [5 ns full width at half maximum (FWHM) and 10(9) W/cm(2) peak irradiance], the calculated results show that the characteristics of the surface temperature and the evaporation depth are very similar even when the ambient pressure varies greatly. The influence of the ambient pressure on the fraction of absorbed laser energy is also small. The maximum ablated material vapor density in the plume is influenced slightly by the different pressures. Before 40 ns, the maximum plume temperature for various ambient pressures is in the order of a few 10(4) K. However, the effect of ambient pressure on the plume length is quite large. A specific calculation for a Gaussian-shaped laser pulse with 6 ns FWHM and 2.76x10(9) W/cm(2) peak irradiance is made. The calculated evaporation depth agrees well with the experimental data. Therefore, the model can be useful to predict trends in target and plume (plasma) characteristics, which are difficult to obtain experimentally for various ambient pressures. (c) 2006 American Institute of Physics.