Lawrence-Gurney模型给出了求解激光驱动飞片速度的方程组。文章从理论和试验两个方面对Lawrence-Gurney模型的适用性进行了分析,发现该模型不能较好地描述厚度为10μm以下飞片的驱动过程。主要原因是Lawrence-Gurney模型对激光与飞片的具体相互作用过程进行了简化假设,依据能量守恒和动量守恒定律建立数学方程组,而这些假设条件和近似求解条件对于厚度小于10μm的飞片均不能很好地成立,导致对飞片速度、能量耦合效率、冲量耦合系数和飞片烧蚀深度随激光能量变化的理论预估结果与试验结果偏差较大,需要进行修正。
The Lawrence-Gurney model is capable of, through mathematical equations, predicting the final velocity of flyers accelerated by laser beams. This paper, through both theoretical analysis and experiments, studies the applicability of the L-G model. It is shown that L-G model can not describe the driving process well for flyers thinner than 10 μm, due to the fact that the interactions between the laser beam and the flyer are ignored along with a number of simplified conditions to deduce the equations based on the energy and momentum conservation laws. These assumptions and approximate calculation conditions are not satisfied if the flyer thickness is less than 10μm, which would lead to a considerable error in predicting the change of the flyer velocity, the energy coupling efficiency, the momentum coupling coefficient, and the ablated depth of the flyer with the change of the laser energy. Thus, the L-G model should be corrected.