By use of high intensity XUV radiation from the FLASH free-electron laser at DESY, we have created highly excited exotic states of matter in solid-density aluminum samples. The XUV intensity is sufficiently high to excite an inner-shell electron from a large fraction of the atoms in the focal region. We show that soft-x-ray emission spectroscopy measurements reveal the electronic temperature and density of this highly excited system immediately after the excitation pulse, with detailed calculations of the electronic structure, based on finite-temperature density functional theory, in good agreement with the experimental results.
S. M. Vinko, U. Zastrau, S. Mazevet, J. Andreasson, S. Bajt,
T. Burian, J. Chalupsky, H. N. Chapman,
J. Cihelka, D. Doria, T. Döppner, S. Düsterer, T. Dzelzainis, R. R. Fäustlin, C. Fortmann, E. Förster, E. Galtier, S. H. Glenzer, S. Göde, G. Gregori, J. Hajdu,
V. Hajkova, P. A. Heimann, R. Irsig,
L. Juha, M. Jurek, J. Krzywinski, T. Laarmann, H. J. Lee, R.W. Lee, B. Li, K.-H. Meiwes-Broer, J. P. Mithen, B. Nagler, A. J. Nelson, A. Przystawik, R. Redmer, D. Riley, F. Rosmej, R. Sobierajski, F. Tavella, R. Thiele, J. Tiggesbäumker, S. Toleikis, T. Tschentscher,
L. Vysin, T. J. Whitcher, S. White, J. S. Wark: Electronic structure of an XUV photogenerated solid-density aluminum plasma, Phys. Rev. Lett.
104, 225001 (2010).
