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Observation of Ultrafast Nonequilibrium Collective Dynamics in Warm Dense Hydrogen

Journal Article · · Physical Review Letters
; ; ; ; ;  [1]; ; ; ; ; ; ; ; ; ;  [2]; ;  [3]; ;  [4]
  1. DESY, Notkestr. 85, 22607 Hamburg (Germany)
  2. Institut fuer Physik, Universitaet Rostock, 18051 Rostock (Germany)
  3. L-399, LLNL, University of California, P.O. Box 808, Livermore, California 94551 (United States)
  4. IOQ, Friedrich-Schiller-Universitaet, Max-Wien Platz 1, 07743 Jena (Germany)
We investigate ultrafast (fs) electron dynamics in a liquid hydrogen sample, isochorically and volumetrically heated to a moderately coupled plasma state. Thomson scattering measurements using 91.8 eV photons from the free-electron laser in Hamburg (FLASH at DESY) show that the hydrogen plasma has been driven to a nonthermal state with an electron temperature of 13 eV and an ion temperature below 0.1 eV, while the free-electron density is 2.8x10{sup 20} cm{sup -3}. For dense plasmas, our experimental data strongly support a nonequilibrium kinetics model that uses impact ionization cross sections based on classical free-electron collisions.
OSTI ID:
21386872
Journal Information:
Physical Review Letters, Journal Name: Physical Review Letters Journal Issue: 12 Vol. 104; ISSN 0031-9007; ISSN PRLTAO
Country of Publication:
United States
Language:
English