Absorption of VUV-Fel radiation in warm dense matter

The interaction of ultra-intense 50 fs V-UV-beams with solid-density metal and plasma targets has been simulated, solving Maxwell equations in one-dimensional geometry. An explicit dielectric function is derived describing photo-ionization in addition to collisional absorption by conduction electrons. As an example, heating of thin aluminum foils up to electron temperatures of 450 eV is discussed, including results on emission spectra during and after the heating. The experiments corresponding to the simulations are now in progress at DESY in Hamburg, using the new V-UV Free Electron Laser. (authors)