X-Ray Scattering Measurements of Strong Ion-Ion Correlations in Shock-Compressed Aluminum

T. Ma, T. Döppner, R. W. Falcone, L. Fletcher, C. Fortmann, D. O. Gericke, O. L. Landen, H. J. Lee, A. Pak, J. Vorberger, K. Wünsch, and S. H. Glenzer

Phys. Rev. Lett. 110, 065001 – Published 5 February 2013

Abstract

The strong ion-ion correlation peak characteristic of warm dense matter (WDM) is observed for the first time using simultaneous angularly, temporally, and spectrally resolved x-ray scattering measurements in laser-driven shock-compressed aluminum. Laser-produced molybdenum x-ray line emission at an energy of 17.9 keV is employed to probe aluminum compressed to a density of $ρ > 8 g / {cm}^{3}$ . We observe a well pronounced peak in the static structure factor at a wave number of $k = 4.0 Å^{- 1}$ . The measurements of the magnitude and position of this correlation peak are precise enough to test different theoretical models for the ion structure and show that only models taking the complex interaction in WDM into account agree with the data. This also demonstrates a new highly accurate diagnostic to directly measure the state of compression of warm dense matter.

Received 18 September 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.065001

Authors & Affiliations

T. Ma¹, T. Döppner¹, R. W. Falcone², L. Fletcher², C. Fortmann^1,3, D. O. Gericke⁴, O. L. Landen¹, H. J. Lee⁵, A. Pak¹, J. Vorberger⁴, K. Wünsch⁴, and S. H. Glenzer¹

¹Lawrence Livermore National Laboratory, Livermore, California 94550, USA
²Physics Department, University of California, Berkeley, California 94720, USA
³Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
⁴Centre for Fusion, Space and Astrophysics, Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
⁵SLAC National Accelerator Laboratory, Menlo Park, California 94309, USA