Following the Birth of a Nanoplasma Produced by an Ultrashort Hard-X-Ray Laser in Xenon Clusters

Yoshiaki Kumagai , Hironobu Fukuzawa , Koji Motomura , Denys Iablonskyi , Kiyonobu Nagaya , Shin-Ichi Wada (1) , Yuta Ito , Tsukasa Takanashi , Yuta Sakakibara , Daehyun You , Toshiyuki Nishiyama , Kazuki Asa , Yuhiro Sato , Takayuki Umemoto , Kango Kariyazono , Edwin Kukk , Kuno Kooser , Christophe Nicolas (2) , Catalin Miron (2, 3) , Theodor Asavei (4) , Liviu P. Neagu (5) , Markus Schöffler , Gregor Kastirke , Xiao-Jing Liu , Shigeki Owada (6) , Tetsuo Katayama , Tadashi Togashi , Kensuke Tono (6) , Makina Yabashi (6) , Nikolay Golubev , Kirill Gokhberg (7) , Lorenz S Cederbaum (7) , Alexander Kuleff (7) , Kiyoshi Ueda (8)

1 Graduate school of science
2 SSOLEIL - Synchrotron SOLEIL
3 LIDYL - Laboratoire Interactions, Dynamiques et Lasers (ex SPAM)
4 The University of Queensland
5 NILPRP - National Institute for Plasma and Radiation Physics
6 RIKEN - RIKEN - Institute of Physical and Chemical Research [Japon]
7 PCI - Physikalisch-Chemisches Institut [Heidelberg]
8 IMRAM

X-ray free-electron lasers (XFELs) made available a new regime of x-ray intensities, revolutionizing the ultrafast structure determination and laying the foundations of the novel field of nonlinear x-ray optics. Although earlier studies revealed nanoplasma formation when an XFEL pulse interacts with any nanometer-scale matter, the formation process itself has never been decrypted and its timescale was unknown. Here we show that time-resolved ion yield measurements combined with a near-infrared laser probe reveal a surprisingly ultrafast population (∼12 fs), followed by a slower depopulation (∼250 fs) of highly excited states of atomic fragments generated in the process of XFEL-induced nanoplasma formation. Inelastic scattering of Auger electrons and interatomic Coulombic decay are suggested as the mechanisms populating and depopulating, respectively, these excited states. The observed response occurs within the typical x-ray pulse durations and affects x-ray scattering, thus providing key information on the foundations of x-ray imaging with XFELs.

Domaines: Physique [physics]

Yoshiaki Kumagai, Hironobu Fukuzawa, Koji Motomura, Denys Iablonskyi, Kiyonobu Nagaya, et al.. Following the Birth of a Nanoplasma Produced by an Ultrashort Hard-X-Ray Laser in Xenon Clusters. Physical Review X, 2018, 8 (3), ⟨10.1103/PhysRevX.8.031034⟩. ⟨cea-01881632⟩