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A: Fachverband Atomphysik

A 8: Poster I

A 8.5: Poster

Dienstag, 9. März 2010, 16:30–19:00, Lichthof

Clusters in XUV laser pulses: Electron emission and nanoplasma dynamics — •Mathias Arbeiter und Thomas Fennel — Institute of Physics, University of Rostock

The ionization dynamics of Argon clusters in ultrashort and intense XUV laser pulses is investigated by molecular dynamics simulation. Corresponding experiments^[1] at FLASH free electron laser at λ=32 nm and λ=13 nm with intensities of I=10¹²⁻¹⁴ W/cm² have demonstrated the cluster response to be completely different to the behavior observed in the infrared and the VUV regime, where plasma heating processes dominate the laser- cluster coupling. In contrast, energy absorption due to the excitation of localized electrons, i.e. by the inner ionization processes itself, becomes increasingly important at high photon energy. The resulting signatures in electron energy spectra can be described by a multi-step ionization scheme as long as photoelectrons can escape directly from the cluster potential. Beyond this point, thermalization becomes the dominant process for further electron emission, as is demonstrated by corresponding simulation results.^[2] From these scenarios, promising future experiments will be addressed for XUV pump-and-probe experiments, e.g. for monitoring nanoplasma built-up, cluster expansion and dark plasmon modes.

[1] C. Bostedt et al., Phys. Rev. Lett. 100, 133401 (2008)

[2] M. Arbeiter, Th. Fennel, in preparation