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# Ultrabright X-ray laser scattering for dynamic warm dense matter physics

## Abstract

In megabar shock waves, materials compress and undergo a phase transition to a dense charged-particle system that is dominated by strong correlations and quantum effects. This complex state, known as warm dense matter, exists in planetary interiors and many laboratory experiments (for example, during high-power laser interactions with solids or the compression phase of inertial confinement fusion implosions). Here, we apply record peak brightness X-rays at the Linac Coherent Light Source to resolve ionic interactions at atomic (ångström) scale lengths and to determine their physical properties. Our in situ measurements characterize the compressed lattice and resolve the transition to warm dense matter, demonstrating that short-range repulsion between ions must be accounted for to obtain accurate structure factor and equation of state data. In addition, the unique properties of the X-ray laser provide plasmon spectra that yield the temperature and density with unprecedented precision at micrometre-scale resolution in dynamic compression experiments.

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## Acknowledgements

This work was performed at the Matter at Extreme Conditions (MEC) instrument of the LCLS, supported by the DOE Office of Science, Fusion Energy Science (contract no. SF00515). This work was supported by the DOE Office of Science, Fusion Energy Science (FWP 100182) and partially supported by the DOE Office of Basic Energy Sciences, Materials Sciences and Engineering Division (contract no. DE-AC02-76SF00515). Part of this work was performed with the assistance of the US Department of Energy by Lawrence Livermore National Laboratory (contract no. DE-AC52-07NA27344). This work was also supported by a Laboratory Directed Research and Development grant (11-ERD-050) and the Peter–Paul–Ewald Fellowship of the VolkswagenStiftung.

## Author information

Authors

### Contributions

L.B.F. and S.H.G. co-wrote the manuscript. L.B.F., H.J.L., T.D., E.G., B.N., P.H., S.L.P., T.M., A.P., D.T., T.W., M.W., B.B., U.Z., J.B.H. and S.H.G. performed the experiment. U.Z., T.D. and H.J.L. developed and commissioned the spectrometer. L.B.F. and A.P. analysed the spectra. C.F., M.M., D.A.C., D.O.G., J.V. and G.G. performed calculations and simulations. L.B.F., T.D., M.M., D.A.C., D.O.G., J.V., G.G., R.W.F., C.-C.K., H.N., J.W., P.N., J.B.H. and S.H.G. conceived the experiment and interpreted the results.

### Corresponding authors

Correspondence to L. B. Fletcher or S. H. Glenzer.

## Ethics declarations

### Competing interests

The authors declare no competing financial interests.

## Supplementary information

### Supplementary information

Supplementary information (PDF 2871 kb)

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Fletcher, L., Lee, H., Döppner, T. et al. Ultrabright X-ray laser scattering for dynamic warm dense matter physics. Nature Photon 9, 274–279 (2015). https://doi.org/10.1038/nphoton.2015.41

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• DOI: https://doi.org/10.1038/nphoton.2015.41

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