From microjoules to megajoules and kilobars to gigabars: Probing matter at extreme states of deformation
Physics of Plasmas AIP Publishing 22:9 (2015) 090501
Simulations of in situ x-ray diffraction from uniaxially compressed highly textured polycrystalline targets
Journal of Applied Physics AIP Publishing 118:6 (2015) 065902
Direct Observation of Melting in Shock-Compressed Bismuth With Femtosecond X-ray Diffraction.
Physical review letters 115:9 (2015) 095701
Abstract:
The melting of bismuth in response to shock compression has been studied using in situ femtosecond x-ray diffraction at an x-ray free electron laser. Both solid-solid and solid-liquid phase transitions are documented using changes in discrete diffraction peaks and the emergence of broad, liquid scattering upon release from shock pressures up to 14 GPa. The transformation from the solid state to the liquid is found to occur in less than 3 ns, very much faster than previously believed. These results are the first quantitative measurements of a liquid material obtained on shock release using x-ray diffraction, and provide an upper limit for the time scale of melting of bismuth under shock loading.Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL.
Scientific reports 5 (2015) 11089
Abstract:
The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range, and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width, and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions.Imaging transient melting of a nanocrystal using an X-ray laser.
Proceedings of the National Academy of Sciences of the United States of America 112:24 (2015) 7444-7448