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We report here the first equation of state measurements of Fe$_2$O$_3$ obtained with laser-driven shock compression. The data are in excellent agreement with previous dynamic and static compression measurements at low pressure, and extend the known Hugoniot up to 700 GPa. We observe a large volume drop of $\sim$10% at 86 GPa, which could be associated, according to static compression observations, with the iron spin transition. Our measurements also suggest a change of the Hugoniot curve between 150 and 250 GPa. Above 250 GPa and within our error bars, we do not observe significant modifications up to the maximum pressure of 700 GPa reached in our experiment., Comment: 8 pages, 3 figures, 2 tables

The insulator-metal transition in liquid hydrogen is an important phenomenon to understand the interiors of gas giants, such as Jupiter and Saturn, as well as the physical and chemical behavior of materials at high pressures and temperatures. Here, the path toward an experimental approach is detailed based on spectrally resolved x-ray scattering, tailored to observe and characterize hydrogen metallization in dynamically compressed hydrocarbons in the regime of carbon-hydrogen phase separation. With the help of time-dependent density functional theory calculations and scattering spectra from undriven carbon samples collected at the European x-ray Free-Electron Laser Facility (EuXFEL), we demonstrate sufficient data quality for observing C-H demixing and investigating the presence of liquid metallic hydrogen in future experiments using the reprated drive laser systems at EuXFEL.

The insulator–metal transition in liquid hydrogen is an important phenomenon to understand the interiors of gas giants, such as Jupiter and Saturn, as well as the physical and chemical behavior of materials at high pressures and temperatures. Here, the path toward an experimental approach is detailed based on spectrally resolved x-ray scattering, tailored to observe and characterize hydrogen metallization in dynamically compressed hydrocarbons in the regime of carbon–hydrogen phase separation. With the help of time-dependent density functional theory calculations and scattering spectra from undriven carbon samples collected at the European x-ray Free-Electron Laser Facility (EuXFEL), we demonstrate sufficient data quality for observing C–H demixing and investigating the presence of liquid metallic hydrogen in future experiments using the reprated drive laser systems at EuXFEL.

We present a proof-of-principle study demonstrating x-ray Raman Spectroscopy (XRS) from carbon samples at ambient conditions in conjunction with other common diagnostics to study warm dense matter, performed at the high energy density scientific instrument of the European x-ray Free Electron Laser (European XFEL). We obtain sufficient spectral resolution to identify the local structure and chemical bonding of diamond and graphite samples, using highly annealed pyrolytic graphite spectrometers. Due to the high crystal reflectivity and XFEL brightness, we obtain signal strengths that will enable accurate XRS measurements in upcoming pump-probe experiments with a high repetition-rate, where the samples will be pumped with high-power lasers. Molecular dynamics simulations based on density functional theory together with XRS simulations demonstrate the potential of this technique and show predictions for high-energy-density conditions. Our setup allows simultaneous implementation of several different diagnostic methods to reduce ambiguities in the analysis of the experimental results, which, for warm dense matter, often relies on simplifying model assumptions. The promising capabilities demonstrated here provide unprecedented insights into chemical and structural dynamics in warm dense matter states of light elements, including conditions similar to the interiors of planets, low-mass stars, and other celestial bodies.

Results of the 2018 commissioning and experimental campaigns of the new High Power Laser Facility on the Energy-dispersive X-ray Absorption Spectroscopy (ED-XAS) beamline ID24 at the ESRF are presented. The front-end of the future laser, delivering 15 J in 10 ns, was interfaced to the beamline. Laser-driven dynamic compression experiments were performed on iron oxides, iron alloys and bismuth probed by online time-resolved XAS.

We present a proof-of-principle study demonstrating X-ray Raman Spectroscopy (XRS) from carbon samples at ambient conditions in conjunction with other common diagnostics to study warm dense matter, performed at the High Energy Density scientific instrument of the European X-ray Free Electron Laser (European XFEL). We obtain sufficient spectral resolution to identify the local structure and chemical bonding of diamond and graphite samples, using highly annealed pyrolytic graphite spectrometers. Due to the high crystal reflectivity and XFEL brightness, we obtain signal strengths that will enable accurate XRS measurements in upcoming pump-probe experiments with high repetition-rate, where the samples will be pumped with high-power lasers. Molecular dynamics simulations based on density functional theory together with XRS simulations demonstrate the potential of this technique and show predictions for high-energy-density conditions. Our setup allows simultaneous implementation of several di erent diagnostic methods to reduce ambiguities in the analysis of the experimental results, which, for warm dense matter, often relies on simplifying model assumptions. The promising capabilities demonstrated here provide unprecedented insights into chemical and structural dynamics in warm dense matter states of light elements, including conditions similar to the interiors of planets, low-mass stars and other celestial bodies.

Deep inside planets extreme material states can be found: pressures up to hundreds of GPa and temperatures up to thousands and ten thousands of K are common. From all planets, the Earth is most investigated, but open questions e.g. regarding the crystallographic structure and composition of the core material remain. The Earth’s core consists mostly of iron, supposedly in an alloy with a substantial amount of nickel. However, results from seismological studies suggest the presence of lighter elements (like H, C, O ,Si and S), too. Not only for geophysics but also for modelling terrestrial planets found in extrasolar systems, the study of the high-pressure high-temperature phase diagram of iron and its alloys is of importance. Bright X-ray sources in combination with high-power optical laser provide unique possibilities for creating and probing such extreme material states and their properties in the laboratory. In 2018, the High Power Laser Facility (HPLF) at the European Synchrotron Radiation Facility (ESRF) has started to be established. High quality X-ray absorption spectroscopy of dynamically compressed matter together with additional shock diagnostics will give insight into structural and electronic changes of the material as well as will give information about generated temperatures and pressures. This talk presents results from first commissioning experiments at this new outstanding facility, where laser shock compressed high-energy-density states of iron and its alloys with nickel and silicon have been investigated via single-shot X-ray absorption spectroscopy at the iron K edge.

Livre premier : Les premiers temps de la Grèce. 1) L'installation des Grecs. La terre et les hommes 2) Le monde égéen à l'époque des palais crétois 3) Apogée et chute du monde mycénien Livre deuxième : Un nouveau monde grec 4) Les problèmes du Haut-Archaïsme / Homère et Hésiode 5) La cité archaïque et l'expansion coloniale 6) Evolution politique et sociale des cités 7) La diversité des cités grecques 8) L'univers religieux de la cité Livre troisième : La Grèce classique 9) L'avènement du Ve siècle 10) Le rayonnement d'Athènes 11) Vivre en Grèce au Ve siècle 12) De la guerre du Péloponnèse à la mort de Socrate 13. Les franges du monde grec 14. L'économie au ive siècle 15) Les transformations de la cité au ive siècle Livre quatrième : Alexandre et le monde hellénistique 16) Philippe, Alexandre et les cités grecques 17) Les grandes monarchies hellénistiques (Egypte exclue), les ligues et les cités 18) Alexandrie et l'Egypte lagide 19. La société hellénistique

Livre premier : Les premiers temps de la Grèce. 1) L'installation des Grecs. La terre et les hommes 2) Le monde égéen à l'époque des palais crétois 3) Apogée et chute du monde mycénien Livre deuxième : Un nouveau monde grec 4) Les problèmes du Haut-Archaïsme / Homère et Hésiode 5) La cité archaïque et l'expansion coloniale 6) Evolution politique et sociale des cités 7) La diversité des cités grecques 8) L'univers religieux de la cité Livre troisième : La Grèce classique 9) L'avènement du Ve siècle 10) Le rayonnement d'Athènes 11) Vivre en Grèce au Ve siècle 12) De la guerre du Péloponnèse à la mort de Socrate 13. Les franges du monde grec 14. L'économie au ive siècle 15) Les transformations de la cité au ive siècle Livre quatrième : Alexandre et le monde hellénistique 16) Philippe, Alexandre et les cités grecques 17) Les grandes monarchies hellénistiques (Egypte exclue), les ligues et les cités 18) Alexandrie et l'Egypte lagide 19. La société hellénistique

Livre premier : Les premiers temps de la Grèce. 1) L'installation des Grecs. La terre et les hommes 2) Le monde égéen à l'époque des palais crétois 3) Apogée et chute du monde mycénien Livre deuxième : Un nouveau monde grec 4) Les problèmes du Haut-Archaïsme / Homère et Hésiode 5) La cité archaïque et l'expansion coloniale 6) Evolution politique et sociale des cités 7) La diversité des cités grecques 8) L'univers religieux de la cité Livre troisième : La Grèce classique 9) L'avènement du Ve siècle 10) Le rayonnement d'Athènes 11) Vivre en Grèce au Ve siècle 12) De la guerre du Péloponnèse à la mort de Socrate 13. Les franges du monde grec 14. L'économie au ive siècle 15) Les transformations de la cité au ive siècle Livre quatrième : Alexandre et le monde hellénistique 16) Philippe, Alexandre et les cités grecques 17) Les grandes monarchies hellénistiques (Egypte exclue), les ligues et les cités 18) Alexandrie et l'Egypte lagide 19. La société hellénistique

Livre premier : Les premiers temps de la Grèce. 1) L'installation des Grecs. La terre et les hommes 2) Le monde égéen à l'époque des palais crétois 3) Apogée et chute du monde mycénien Livre deuxième : Un nouveau monde grec 4) Les problèmes du Haut-Archaïsme / Homère et Hésiode 5) La cité archaïque et l'expansion coloniale 6) Evolution politique et sociale des cités 7) La diversité des cités grecques 8) L'univers religieux de la cité Livre troisième : La Grèce classique 9) L'avènement du Ve siècle 10) Le rayonnement d'Athènes 11) Vivre en Grèce au Ve siècle 12) De la guerre du Péloponnèse à la mort de Socrate 13. Les franges du monde grec 14. L'économie au ive siècle 15) Les transformations de la cité au ive siècle Livre quatrième : Alexandre et le monde hellénistique 16) Philippe, Alexandre et les cités grecques 17) Les grandes monarchies hellénistiques (Egypte exclue), les ligues et les cités 18) Alexandrie et l'Egypte lagide 19. La société hellénistique

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Bibliogr. p. 179-181

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