title: Free-electron X-ray laser measurements of collisional-damped plasmons in isochorically heated warm dense matter.
abstract: We present the first highly resolved measurements of the plasmon spectrum in an ultrafast heated solid. Multi-keV x-ray photons from the Linac Coherent Light Source have been focused to one micrometer diameter focal spots producing solid density aluminum plasmas with a known electron density of n_{e}=1.8×10^{23}  cm^{-3}. Detailed balance is observed through the intensity ratio of up- and down-shifted plasmons in x-ray forward scattering spectra measuring the electron temperature. The plasmon damping is treated by electron-ion collision models beyond the Born approximation to determine the electrical conductivity of warm dense aluminum.
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.|Institut für Physik, Universität Rostock, 18051 Rostock, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Sperling
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
authors.forename: E J
authors.initials: EJ
authors.lastname: Gamboa
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Lee
authors.affiliation: Nuclear Data Section, Division of Physical and Chemical Sciences, International Atomic Energy Agency, A-1400 Vienna, Austria.
authors.forename: H K
authors.initials: HK
authors.lastname: Chung
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
authors.forename: E
authors.initials: E
authors.lastname: Galtier
authors.affiliation: Institut für Physik, Universität Rostock, 18051 Rostock, Germany.|International IT University, 050040 Almaty, Kazakhstan.
authors.forename: Y
authors.initials: Y
authors.lastname: Omarbakiyeva
authors.affiliation: Institut für Physik, Universität Rostock, 18051 Rostock, Germany.|University of Western Australia, WA 6009 Crawley, Australia.
authors.forename: H
authors.initials: H
authors.lastname: Reinholz
authors.affiliation: Institut für Physik, Universität Rostock, 18051 Rostock, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Röpke
authors.affiliation: European XFEL, Albert-Einstein-Ring 19, 22761 Hamburg, Germany.
authors.forename: U
authors.initials: U
authors.lastname: Zastrau
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
authors.forename: J
authors.initials: J
authors.lastname: Hastings
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
authors.forename: L B
authors.initials: LB
authors.lastname: Fletcher
authors.affiliation: SLAC National Accelerator Laboratory, 2575 Sand Hill Road, MS 72 Menlo Park, California 94025, USA.
authors.forename: S H
authors.initials: SH
authors.lastname: Glenzer