Shock waves from a water-confined laser-generated plasma
Shock waves from a water-confined laser-generated plasma
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DOI：
10.1063/1.366113
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发表时间：
1997-09-15
影响因子：
3.2
通讯作者：
Bartnicki, E
中科院分区：
文献类型：
--
作者：
Berthe, L;Fabbro, R;Bartnicki, E
本文研究了25-30 ns/40 J/λ =1.064 μ m脉冲激光束在水约束条件下激光等离子体产生高振幅冲击波的情况。实验测量的时间和空间轮廓的诱导冲击波的激光冲击处理的材料的这一制度进行使用任何反射器系统的测速干涉仪系统。在10 GW/cm（2）激光强度阈值以上，峰值压力饱和，而压力脉冲持续时间被封闭水中出现的寄生等离子体减少。用快速照相机系统对相互作用区的观察表明，这种击穿等离子体主要发生在水的表面而不是水体积内，限制了该过程的效率。该等离子体吸收入射激光能量，并且到达目标的功率密度随着功率密度的增加而逐渐减小，同时冲击波持续时间相应地减小。这两个压力测量和等离子体观测可以解释目前的限制，高振幅的冲击波产生的激光等离子体中的水约束模式和开放的新的研究领域的理解击穿等离子体的影响在表面的封闭水。(C)1997年美国物理学会。
Generation of a high amplitude shock wave by laser plasma in a water confinement regime has been investigated for an incident 25-30 ns/40 J/lambda=1.064 mu m pulsed laser beam. Experimental measurements of temporal and spatial profiles of induced shock waves for this regime of laser shock processing of materials were performed using a velocimetry interferometer system for any reflector system. Above a 10 GW/cm(2) laser intensity threshold, a saturation of the peak pressure is shown to occur while the pressure pulse duration is reduced by parasitic plasma occurring in the confining water. The observation of the interaction zone with a fast camera system shows that this breakdown plasma, which mainly occurs at the very surface of the water rather than within the water volume, limits the efficiency of the process. This plasma absorbs the incident laser energy, and the power density reaching the target gradually decreases with increasing power densities while the shock-wave duration is correspondingly reduced. Both pressure measurements and plasma observations allow explaining the current limit of high amplitude shock-waves generation by laser plasma in the water-confinement mode and open new research areas for the understanding of breakdown plasma effects at the surface of the confining water. (C) 1997 American institute of Physics.