X射线烧蚀泡沫-固体靶增压机理研究

X射线烧蚀泡沫-固体靶时界面失配会使得泡沫与固体靶中压力增加, 这一现象可用于研究高压下物质的状态方程. 本文以CH泡沫-Al固体靶为例, 研究了X射线烧蚀双层靶时的增压现象. 提出仅当泡沫中有冲击波产生时, 在固体靶中才会有增压现象出现. 文中基于冲击波强波近似, 理论分析了冲击波过界面情况与冲击波、稀疏波作用过程, 得到增压倍数与材料密度, 多方气体指数的近似表达式. 同时表明固体靶中增压产生的冲击波为高压脉冲, 会被紧跟热波的稀疏波追赶并稀疏. MULTI一维计算结果验证了该结论.

Pressure increase in foam-solid target from X-ray driven shock waves

A strong pressure increase is produced by X-ray heating a foam-solid target in comparison with heating directly the solid target, due to impedance mismatch at the foam-solid interface. We study the pressure increase of CH foam-aluminum target, and find that only by shock present in foam can the ablative pressure in aluminum increase. In this paper an analytical model based on strong wave assumption is developed to study the shock impedance mismatching crossing the interface and the interaction of rarefaction with shock. We evaluate the shock pressure amplified in the aluminum layer as a function of density and adiabatic exponent, and show that the amplified pressure is a short high pressure pulse which is destroyed by rarefactions. This is in agreement with simulation results by MULTI code.