靶与光斑尺寸对激光冲量影响的数值模拟

摘要

The plasma flow field of solid target in atmosphere under impulse laser irradiation was computed.The flow is governed by the 2-D Reynolds averaged Navier-Stokes (NS)equations.The k-εturbulence model was used for turbulence simula-tions.To split the viscosity flux and the convective flux of the NS equations,the second order central scheme and the ROE scheme were adopted respectively.With the implicit Gauss-Seidel scheme,the code was advanced in time.The 2-D hydrokinetics process of laser plasma was presented in this paper by numerical simulation.The influence of target dimension and laser spot size on laser impulse was discussed.The results indicated that laser impulse increases generally with target dimension.%采用二维雷诺平均 N-S方程,数值模拟研究了大气条件下短脉冲激光与固体靶相互作用所产生等离子体的动力学过程.采用k-ε两方程模型用于湍流的数值模拟,分别利用 ROE格式和二阶中心格式对对流通量和粘性通量进行离散处理;用高斯-赛德尔隐式格式对方程进行时间推进求解.数值模拟给出了激光引发靶蒸气等离子体侧向膨胀、稀疏等二维流体动力学过程的物理图像,讨论了靶与光斑尺寸对脉冲激光冲量的影响.结果表明,不同宽度固体靶受到的激光冲量有很大差异,固体靶宽度越大,受到的激光冲量也越大.