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X-ray line spectral signatures of plasmas driven by high-intensity ultra-short laser pulses.

机译：由高强度超短激光脉冲驱动的等离子体的X射线线光谱特征。

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In this dissertation we report on our atomic-kinetics and X-ray line spectra modeling work in the context of plasmas generated by high-intensity, ultrashort-duration pulsed lasers. We focus on characterizing the properties of X-ray line emissions (i.e., intensity, broadening, and polarization) as signatures of plasma conditions, discuss the relevant atomic processes, and introduce atomic kinetics as a means for their quantitative assessment. This also requires the knowledge of detailed line shapes including the effects of Doppler and natural broadening, Stark broadening, line shifts and radiation transport. A suite of time-dependent, collisional-radiative atomic kinetics and spectral codes, CRAK/SPECTRUM, were developed. We applied these codes to the analysis of K-shell aluminum X-ray line spectra recorded in experiments using layered targets performed at the Max-Planck-Institut für Quantenoptik. Modeling calculations indicate that red line shifts observed in these experiments cannot be explained by shifts in the centers of gravity of composite spectral features due to enhanced satellite contributions, but are consistent with line shift effects in resonance and satellite lines.; We discuss the mechanism of polarized X-ray line emission in plasmas, its connection to plasma anisotropy, and introduce an atomic kinetics model and code (POLAR) based on the population kinetics of magnetic sublevels. POLAR represents a multi-level, multi-process approach to the problem of polarized spectra in plasmas, and hence it is well suited for plasma applications where cascade effects and alignment transfer can become important. Polarization degrees of X-ray spectral lines computed with POLAR were successfully benchmarked against calculations done with other formalisms, and experimental results obtained at the EBIT facility of Lawrence Livermore National Laboratory. We investigate the polarization of He-like Si X-ray satellite lines as spectral signatures of anisotropy in the electron distribution function. A comprehensive modeling study has been performed taking into account hydrodynamics and electron kinetics. We find that two satellite lines connecting singlet states develop a noticeable polarization while the triplet lines remain unpolarized. These results suggest a scenario where triplet lines could be used as a reference while the singlets could be used as polarized markers of plasma anisotropy.
机译：在这篇论文中，我们报告了在高强度，超短持续时间脉冲激光产生的等离子体的背景下，我们的原子动力学和X射线线谱建模工作。我们专注于表征X射线线发射的特性（即强度，展宽和极化）作为等离子体条件的特征，讨论相关的原子过程，并引入原子动力学作为对其定量评估的手段。这也需要了解详细的线形，包括多普勒效应和自然展宽，斯塔克展宽，线位移和辐射传输的影响。开发了一套随时间变化的碰撞辐射原子动力学和光谱代码CRAK / SPECTRUM。我们将这些代码应用于在Max-Planck-InstitutfürQuantenoptik进行的分层目标实验中记录的K壳铝X射线线谱分析。建模计算表明，由于增加了卫星的贡献，这些实验中观察到的红线偏移不能用复合频谱特征的重心偏移来解释，但与共振和卫星线的线偏移效应相一致。我们讨论了等离子体中X射线极化线发射的机理，其与等离子体各向异性的关系，并基于磁性子能级的种群动力学介绍了原子动力学模型和代码（POLAR）。 POLAR代表了解决等离子体中极化光谱问题的一种多层次，多过程的方法，因此它非常适合于其中级联效应和对准转移可能变得很重要的等离子体应用。通过POLAR计算的X射线光谱线的偏振度已成功与其他形式主义进行的计算进行了基准比较，并在劳伦斯·利弗莫尔国家实验室的EBIT设施中获得了实验结果。我们调查像He一样的X射线卫星线的极化，作为电子分布函数中各向异性的光谱特征。考虑到流体动力学和电子动力学，已经进行了全面的建模研究。我们发现连接单线态的两条卫星线会产生明显的极化，而三线态线保持非极化。这些结果表明了一种方案，其中三线态谱系可以用作参考，而单线态谱系可以用作血浆各向异性的极化标记。

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