X-ray Thomson scattering measurements from shock-compressed deuterium

Journal Article · Fri May 25 00:00:00 EDT 2012 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4707855· OSTI ID:22004072

Davis, P; Doeppner, T; Rygg, J R; Fortmann, C; Unites, W; Salmonson, J; Collins, G W; Landen, O L; Falcone, R W; Glenzer, S H ^[1]

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1. University of California, Berkeley. Berkeley, CA, 94720 (United States)

X-ray Thomson scattering has recently been shown to be an effective method of diagnosing a variety of high energy density plasma conditions. We apply this powerful technique to the widely studied problem of shock-compressed liquid deuterium. The behavior of deuterium under extreme conditions has received considerable attention due to its central role in models of giant planets and the importance of the high-pressure insulator-metal transition. We have used spectrally resolved x-ray scattering from electron-plasma waves to perform microscopic observations of ionization during compression. In these experiments, a single shock was launched in cryogenic deuterium reaching compressions of 3x. The 2 keV Ly-{alpha} line in silicon was used as an x-ray source in a forward scattering geometry. In addition to elastic scattering from tightly bound electrons, this low probe energy accessed the collective plasmon oscillations of delocalized electrons. Inelastic scattering from the plasmons allowed accurate measurements of the free electron density through the spectral position of the resonance and provided an estimate of the temperature through its ratio with the elastic feature. Combined with velocity interferometry from the reflective shock front, this lead to a direct determination of the ionization state. We compare the measured ionization conditions with computational models. Additionally, we discuss the possibility of using this technique to determine electrical conductivity and to directly observe pressure-induced molecular dissociation along the Hugoniot.

• OSTI ID: 22004072
• Journal Information: AIP Conference Proceedings, Vol. 1438, Issue 1; Conference: 17. international conference on atomic processes in plasmas (ICAPIP), Belfast, Northern Ireland (United Kingdom), 19-22 Jul 2011; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
74 ATOMIC AND MOLECULAR PHYSICS
COMPARATIVE EVALUATIONS
DEUTERIUM
ELASTIC SCATTERING
ELECTRIC CONDUCTIVITY
ELECTRON DENSITY
ELECTRON PLASMA WAVES
ELECTRON TEMPERATURE
ENERGY DENSITY
ION TEMPERATURE
IONIZATION
KEV RANGE
PLASMA
PLASMA DENSITY
PLASMA DIAGNOSTICS
PLASMA PRESSURE
PLASMONS
SHOCK WAVES
THOMSON SCATTERING
X-RAY DIFFRACTION
X-RAY SOURCES