标题： 逆向传播辐射激波实验在奥里翁激光器上以及辐射前导区的形成 显示英文标题

标题： Counter-propagating radiative shock experiments on the Orion laser and the formation of radiative precursors

摘要： 我们介绍了新的实验结果，用于研究辐射激波、反向激波和辐射前导区的动力学特性。 使用位于英国AWE Aldermaston的Orion高功率激光器对固体活塞进行激光烧蚀，以将辐射激波驱动进入初始压力在$0.1$和$1.0 \ bar$之间的气体腔体，并使用不同的惰性气体。 激波以{$80 \pm 10 \ km/s$}的速度传播，并经历了强烈的辐射冷却，导致激波后的压缩度为{ $\times 25 \pm 2$}。 结合X射线背光、光学自发光条纹成像和干涉测量（多帧和条纹成像）技术，同时研究了激波前沿和辐射前导区。 这些实验展示了一种新的配置，用于产生反向传播的辐射激波，从而可以研究反向激波，并为数值验证提供了一个独特的平台。 此外，辐射激波能够自由扩展到一个大的气体体积中，而不会受到气体腔壁的限制。 这使得可以研究激波的三维效应，从原则上讲，这可能导致与天体物理现象更直接的比较。 通过保持不同气体填充之间的恒定质量密度，激波演化出相似的流体力学特性，但发现辐射前导区在高原子序数气体中显著延伸得更远（氙气中的辐射前导区比氖气长$\sim$$4$ 倍）。 最后，给出了1-D和2-D辐射流体动力学模拟，显示与实验数据有良好的一致性。 显示英文摘要

摘要： We present results from new experiments to study the dynamics of radiative shocks, reverse shocks and radiative precursors. Laser ablation of a solid piston by the Orion high-power laser at AWE Aldermaston UK was used to drive radiative shocks into a gas cell initially pressurised between $0.1$ and $1.0 \ bar$ with different noble gases. Shocks propagated at {$80 \pm 10 \ km/s$} and experienced strong radiative cooling resulting in post-shock compressions of { $\times 25 \pm 2$}. A combination of X-ray backlighting, optical self-emission streak imaging and interferometry (multi-frame and streak imaging) were used to simultaneously study both the shock front and the radiative precursor. These experiments present a new configuration to produce counter-propagating radiative shocks, allowing for the study of reverse shocks and providing a unique platform for numerical validation. In addition, the radiative shocks were able to expand freely into a large gas volume without being confined by the walls of the gas cell. This allows for 3-D effects of the shocks to be studied which, in principle, could lead to a more direct comparison to astrophysical phenomena. By maintaining a constant mass density between different gas fills the shocks evolved with similar hydrodynamics but the radiative precursor was found to extend significantly further in higher atomic number gases ($\sim$$4$ times further in xenon than neon). Finally, 1-D and 2-D radiative-hydrodynamic simulations are presented showing good agreement with the experimental data.