X-ray Thomson scattering studies on spin-singlet stabilization of highly compressed H-like Be ions heated to two million degrees Kelvin
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| Formato: | Preprint |
| Publicado: |
2025
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| _version_ | 1866910927118401536 |
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| author | Dharma-wardana, M. W. C. Klug, Dennis. D. |
| author_facet | Dharma-wardana, M. W. C. Klug, Dennis. D. |
| contents | Experiments at the US National Ignition Facility (NIF) [Döppner et al., Nature {\bf 618}, 270-275 (2023)] have created highly compressed hot hydrogen-like Be plasmas. Published analyses of the the NIF experiment have used finite-$T$ multi-atom density-functional theory (DFT) with Molecular dynamics (MD), and Path-Integral Monte Carlo (PIMC) simulations. These methods are very expensive to implement and often lack physical transparency. Here we (i) relate their results to simpler first-principles average-atom results, (ii) establish the feasibility of rapid data analysis, with good accuracy and gain in physical transparency, and (iii) show that the NIF experiment reveals high-$T$ spin-singlet pairing of hydrogen-like Be ions with near neighbours. Our analysis predicts such stabilization over a wide range of compressed densities for temperatures close to two million Kelvin. Calculations of structure factors $S(k)$ for electrons or ions, the Raleigh weight and other quantities of interest to X-ray Thomson scattering are presented. We find that the NIF data at the scattering wavevector $k_{sc}$ of 7.89 Å$^{-1}$ are more consistent with a density of $20\pm2$ g/cm$^3$, mean ionization $\bar{Z}=$3.25, at a temperature of $\simeq$ 1,800,000 K than the 34 g/cm$^3, \bar{Z}=3.4$ proposed by the NIF team. The relevance of ion-electron coupled-modes in studying small $k_{sc}$ data is indicated. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2502_16693 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | X-ray Thomson scattering studies on spin-singlet stabilization of highly compressed H-like Be ions heated to two million degrees Kelvin Dharma-wardana, M. W. C. Klug, Dennis. D. Materials Science Solar and Stellar Astrophysics Plasma Physics Experiments at the US National Ignition Facility (NIF) [Döppner et al., Nature {\bf 618}, 270-275 (2023)] have created highly compressed hot hydrogen-like Be plasmas. Published analyses of the the NIF experiment have used finite-$T$ multi-atom density-functional theory (DFT) with Molecular dynamics (MD), and Path-Integral Monte Carlo (PIMC) simulations. These methods are very expensive to implement and often lack physical transparency. Here we (i) relate their results to simpler first-principles average-atom results, (ii) establish the feasibility of rapid data analysis, with good accuracy and gain in physical transparency, and (iii) show that the NIF experiment reveals high-$T$ spin-singlet pairing of hydrogen-like Be ions with near neighbours. Our analysis predicts such stabilization over a wide range of compressed densities for temperatures close to two million Kelvin. Calculations of structure factors $S(k)$ for electrons or ions, the Raleigh weight and other quantities of interest to X-ray Thomson scattering are presented. We find that the NIF data at the scattering wavevector $k_{sc}$ of 7.89 Å$^{-1}$ are more consistent with a density of $20\pm2$ g/cm$^3$, mean ionization $\bar{Z}=$3.25, at a temperature of $\simeq$ 1,800,000 K than the 34 g/cm$^3, \bar{Z}=3.4$ proposed by the NIF team. The relevance of ion-electron coupled-modes in studying small $k_{sc}$ data is indicated. |
| title | X-ray Thomson scattering studies on spin-singlet stabilization of highly compressed H-like Be ions heated to two million degrees Kelvin |
| topic | Materials Science Solar and Stellar Astrophysics Plasma Physics |
| url | https://arxiv.org/abs/2502.16693 |