标题： 揭示激光驱动冲击和释放铜的温度和相变边界：来自高达300 GPa的超快X射线吸收光谱的见解 显示英文标题

标题： Unveiling temperature and phase boundaries in laser-driven shocked and released copper: insights from ultra-fast X-ray Absorption Spectroscopy up to 300 GPa

摘要： 铜是一种在工业中广泛使用的材料，因其优异的热性和电性而被广泛应用。研究铜（Cu）在高温高压下的性质对于核聚变研究具有重要意义，因为在超高速撞击中使用的弹丸和飞片通常由铜制成，铜也用于核聚变靶的设计。最近，在冲击压缩的铜中通过X射线衍射检测到了固态（面心立方）-固态（体心立方）相变。在此，我们介绍了利用单脉冲（100皮秒半高全宽）X射线吸收光谱（XAS）对冲击压缩铜进行的研究，压力高达300 GPa，温度高达7100 K。基于XAS光谱的分析，我们在Hugoniot线上提供了结构识别和体积温度测量，直至熔化。在释放条件下收集的XAS光谱，即在冲击波突破时间之后的时间点，有助于确定实验中的面心立方-体心立方和固态-液态相边界。特别是，我们在位于237（40）GPa和5750（1130）K之间以及261（27）GPa和6240（1155）K之间的熔化平台首次报告了冲击压缩铜的体积温度测量，并在300 GPa和7100 K的液态铜中进行了测量。 显示英文摘要

摘要： Cu is an ubiquitous material used in industry for its great thermal and electrical properties. Studying the high-pressure high temperature properties of copper (Cu) is relevant for nuclear fusion research as projectiles and flyers used in hypervelocity impacts are generally made of copper, where it is used also in the design of the nuclear fusion targets. Recently, a solid (fcc)-solid (bcc) phase transition has been detected in shock compressed Cu with X-Ray Diffraction. Here, we present a study on shock compressed copper up to 300 GPa and 7100 K probed by single pulse (100 ps FWHM) X-ray Absorption Spectroscopy (XAS). Based on the analysis of the XAS spectra, we provide structural identification and bulk temperature measurements along the Hugoniot up to the melting. The collection of XAS spectra under release conditions, i.e. at later times than the breakout time of the shock wave, helped constraining the experimental fcc-bcc and solid-liquid phase boundaries. In particular, we report the first bulk temperature measurement in shock compressed copper on the melting plateau located between 237(40) GPa and 5750(1130) K and 261 (27) GPa and 6240 (1155) K and on liquid copper at 300 GPa and 7100 K.