激光驱动的冲击波稳定性的数值模拟研究

Numerical Simulation Study of the Stability of Laser-Driven Shock Waves

激光驱动的冲击波进行高压物态方程（EOS）研究中，为保证高压物态方程的精确测量，需要在实验中保证样品中冲击波的稳定性。利用一维辐射流体力学程序MULTI对功率密度为8．1×10-13w／cm2、波长为1．053μm、脉宽为1．0ns的准高斯型脉冲激光驱动的冲击波在各种厚度的平面固体A1靶中传播的稳定性进行了模拟研究。研究表明在阻抗匹配靶的设计中要保证样品中测得的冲击波的稳定性，衬底的厚度应当大于冲击波在靶中加速传播的距离，而样品的厚度应当近似等于冲击波在靶中稳定传播的距离，这样就可使样品中测得的冲击波的平均速度与样品中的稳定传播速度基本一致。

To get the accurate measurement of the equation of state （EOS） by using the laser-driven shock wave, it is necessary to guarantee the stability of shock propagation in sample target. Using one dimensional radiation hydrodynamics code MULTI, the stability of the shock wave propagation in planar A1 targets driven by the laser power densities of 8.1 × 10-13 W/cm ,with 1. 053μm wavelength, ins Gaussian pulse width is studied. The simulation results show that thickness of the substrate should be greater than the shock waves acceleration propagation distance, and the thickness of the sample should be approximately equal to the shock waves stable propagation distance in the design of impedance-match targets, in order to ensure the average velocity of shock waves in the sample approximately equals to the stable transmission velocity.