AI 中文总结
研究超相对论激光与物质相互作用中纳米结构靶产生质子情况，通过ELI-NP设施实验及三维粒子模拟，对比有无等离子体镜时纳米线靶和平坦靶的质子能谱与角分布，发现纳米线靶性能更优。
AI 中文摘要
激光驱动纳米结构固体靶产生质子的过程已被广泛研究，但其在拍瓦级设施实际时间对比度条件下的性能仍是一个悬而未决的问题。我们在ELI-NP设施上进行了实验研究，使用峰值强度约为3×10²¹W/cm²的飞秒激光脉冲，从纳米结构和平坦固体靶中产生质子。比较了两种对比度情况下的质子能谱：无等离子体镜时约为10⁻¹⁰，有单等离子体镜时约为10⁻¹³。重要的是，在两种对比度水平下，纳米线靶的截止能量都有可测量的增强，表明纳米线靶对中等预脉冲强度具有鲁棒性。同时，对能量分辨角分布的研究表明，纳米线促进了更定向的发射，沿靶法线方向有更高通量的高能质子，而平坦靶产生更宽的角分布。结果得到了三维粒子模拟的有力支持和解释。
英文摘要
Laser-driven proton acceleration from nanostructured solid targets has been extensively studied, yet its performance under realistic temporal contrast conditions at petawatt-class facilities remains an open question. We present an experimental investigation of proton generation from nanostructured and flat solid targets performed at the ELI-NP facility using femtosecond laser pulses at peak intensities of $\sim 3\times10^{21}$ \wcm. Proton spectra are compared for two contrast regimes: $\sim 10^{-10}$ without plasma mirror and $\sim 10^{-13}$ with single plasma mirror. Importantly, measurable enhancement in the cutoff energy persists for the nanowire targets at both contrast levels, indicating robustness of nanowire targets against moderate pre-pulse intensities. Alongside, study of energy resolved angular distribution reveals that nanowires promote more directional emission with higher flux of high-energy protons along the target normal, while flat targets produce broader angular distributions. The results are well supported and explained by 3D particle-in-cell simulations.
