8-12 July 2019
Cité des Congrès
Europe/Paris timezone

Direct observations of polymorphism and melting of shock-compressed silicates from ultrafast X-ray diffraction

12 Jul 2019, 10:15
15m
Salle KL (Cité des Congrès)

Salle KL

Cité des Congrès

Speaker

Dr Jean-Alexis Hernandez (LULI, Ecole Polytechnique, CNRS)

Description

Constraining shock-induced transformations of major silicates and their kinetics is necessary to constrain planetary formation models of the terrestrial planets and to understand how meteorites and planetary surfaces have been affected by repetitive shocks. The recent coupling of ultrafast in situ X-ray diffraction (XRD) and shock compression techniques (gas guns and laser facilities) enables the direct investigation of transition mechanisms at short time-scales (from hundreds of picoseconds to hundreds of nanoseconds). In this study, we probed the structure at peak pressure of shocked SiO2 and MgSiO3 glasses and of their crystalline forms (respectively α-quartz and enstatite) by coupling ultrafast XRD to laser-driven shock compression at LCLS MEC end-station of SLAC XFEL facility (Stanford, USA). Our results provide strong insights on the phase transformation mechanisms and kinetics in shocked silicates. I will compare them to theoretical investigations and experimental measurements obtained under static compression, and I will discuss their implications in shock metamorphism and planetary science.

Choix de session parallèle 6.4 Résultats scientifiques récents obtenus avec les XFEL

Primary authors

Dr Jean-Alexis Hernandez (LULI, Ecole Polytechnique, CNRS) Dr Guillaume Morard (Sorbonne Université) Mr Marco Guarguaglini (LULI, Ecole Polytechnique, CNRS) Dr Roberto Alonso-Mori (SLAC National Accelerator Laboratory) Dr Alessandra Benuzzi-Mounaix (LULI, Ecole Polytechnique, CNRS) Dr Riccardo Bolis (LULI, Ecole Polytechnique, CNRS) Dr Guillaume Fiquet (Sorbonne Université) Dr Eric Galtier (SLAC National Accelerator Laboratory) Dr Arianna Gleason (SLAC National Accelerator Laboratory) Dr Siegfried Glenzer (SLAC National Accelerator Laboratory) Prof. François Guyot (Sorbonne Université) Dr B. K. Ko (Arizona State University) Dr Hae Ja Lee (SLAC National Accelerator Laboratory) Prof. Wendy Mao (Stanford Institute for Materials and Energy Sciences) Dr Bob Nagler (SLAC National Accelerator Laboratory) Prof. Norimasa Osaki (Graduate School of Engineering, Osaka University) Ms Anja Schulster (Helmholtz-Zentrum Dresden-Rossendorf) Prof. S. H. Shim (Arizona State University) Dr Tommaso Vinci (LULI, Ecole Polytechnique, CNRS) Dr Alessandra Ravasio (LULI, Ecole Polytechnique, CNRS)

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