Oral
Structural Complexity of Ultra High-Pressure Magnesium on NIF | Authors: Jon Eggert (LLNL - Lawrence Livermore National Laboratory) ; Martin Gorman (LLNL - Lawrence Livermore National Laboratory) ; Amy Lazicki (LLNL - Lawrence Livermore National Laboratory) ; David Mcgonegle (UNIVERSITY OF OXFORD - University of Oxford) ; Stanimir Bonev (LLNL - Lawrence Livermore National Laboratory) ; Sabri Elatresh (CORNELL UNIVERSITY - Cornell University) ; Justin Wark (UNIVERSITY OF OXFORD - University of Oxford) ; Marc Cormier (LLNL - Lawrence Livermore National Laboratory) ; Richard Briggs (LLNL - Lawrence Livermore National Laboratory) ; Amy Coleman (LLNL - Lawrence Livermore National Laboratory) ; Rick Kraus (LLNL - Lawrence Livermore National Laboratory) ; Steve Rothman (AWE - AWE) ; David Braun (LLNL - Lawrence Livermore National Laboratory) ; Gilbert Collins (LLE - University of Rochester) ; Patrick Heighway (UNIVERSITY OF OXFORD - University of Oxford) ; Lisa Peacock (AWE - AWE) ; Federica Coppari (LLNL - Lawrence Livermore National Laboratory) ; Ryan Rygg (LLE - University of Rochester) ; Malcolm Mcmahon (EDINBURGH UNIVERSITY - Edinburgh University ) |
Abstract: We dynamically compressed solid magnesium to pressures up to 1.3 TPa (corresponding to 5.5-fold compression) and report in-situ X-ray diffraction measurements on NIF. As compression increases, the electronic wave functions of valence electrons begin to overlap and interact with those of the core electrons, resulting in exotic electronic and complex structural behavior. Ab-initio simulations of Mg predict a series of simple structures above 0.2 GPa; body-centered cubic, face-centered cubic and primitive hexagonal. We observe that Mg adopts a similar series of structures at 0.3, 0.5 and 0.8 TPa, but our results show somewhat more complex diffraction implying distortions from the expected structures. These results demonstrate how experimental advances in dynamic compression can be used to test theoretical structure calculations at conditions inaccessible by static or shock compression techniques. This work was performed under the auspices of the US Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344
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