Diffractive imaging of transient electronic core-shell structures in a   nanoplasma
  We have recorded the coherent diffraction images of individual xenon clusters with intense extreme ultraviolet pulses to elucidate the influence of light-induced electronic changes on the diffraction pattern. Using the FLASH free-electron laser we tuned the wavelength to specific xenon atomic and ionic resonances. The data show the emergence of a transient core-shell structure within the otherwise homogeneous sample. Simulations indicate that ionization and nanoplasma formation result in a cluster shell with strongly altered refraction. The presented resonant scattering approach enables imaging of ultrafast electron dynamics on their natural time scale. 
Daniela Rupp, Leonie Fl\"uckiger, Marcus Adolph, Tais Gorkhover, Maria   Krikunova, Jan Phillipe M\"uller, Maria M\"uller, T...
physics.atm-clus