Zastrau U, Sperling P, Harmand M, Becker A, Bornath T, Bredow R, Dziarzhytski S, Fennel T, Fletcher L B, Förster E, Göde S, Gregori G, Hilbert V, Hochhaus D, Holst B, Laarmann T, Lee H J, Ma T, Mithen J P, Mitzner R, Murphy C D, Nakatsutsumi M, Neumayer P, Przystawik A, Roling S, Schulz M, Siemer B, Skruszewicz S, Tiggesbäumker J, Toleikis S, Tschentscher T, White T, Wöstmann M, Zacharias H, Döppner T, Glenzer S H, Redmer R
Institut für Optik und Quantenelektronik, Friedrich-Schiller-Universität, Max-Wien-Platz 1, 07743 Jena, Germany and SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
Institut für Physik, Universität Rostock, D-18051 Rostock, Germany.
Phys Rev Lett. 2014 Mar 14;112(10):105002. doi: 10.1103/PhysRevLett.112.105002. Epub 2014 Mar 12.
We report on the dynamics of ultrafast heating in cryogenic hydrogen initiated by a ≲300 fs, 92 eV free electron laser x-ray burst. The rise of the x-ray scattering amplitude from a second x-ray pulse probes the transition from dense cryogenic molecular hydrogen to a nearly uncorrelated plasmalike structure, indicating an electron-ion equilibration time of ∼0.9 ps. The rise time agrees with radiation hydrodynamics simulations based on a conductivity model for partially ionized plasma that is validated by two-temperature density-functional theory.
