Düsseldorf 2007 – wissenschaftliches Programm

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SYCP: Symposium Strongly coupled plasmas

SYCP 1: Symposium Strongly Coupled Plasmas

SYCP 1.7: Hauptvortrag

Dienstag, 20. März 2007, 17:30–18:00, 5D

Ionization dynamics of clusters in strong laser fields — •Karl-Heinz Meiwes-Broer, Tilo Döppner, Thomas Fennel, Johannes Passig, and Josef Tiggesbäumker — University of Rostock, Institute of physics, Universitätsplatz 3, 18051 Rostock

Atomic clusters in intense laser fields are a nice playground to study the coupling of intense electromagnetic radiation into matter. In particular, non-stationary plasma effects lead to pronounced dynamics in the optical response. Recent experiments have shown that excitation with optically delayed dual pulses provides a powerful way to control the coupling of the radiation to these finite systems. Both the yield of highly charged atomic ions [1] as well as the kinetic energy of emitted electrons [2] are strongly enhanced for a particular optimal delay. The significance of the temporal structure of the laser field is demonstrated by complementary Vlasov calculations [3] on model systems. These confirm that the distinct maximum in the charging efficiency can be attributed to plasmon-enhanced ionization of the expanding cluster [1].

Furthermore, by using intensity selective scanning the ionization threshold intensities leading to a given atomic charge state are determined. They exhibit a dramatic deviation when compared to the ionzation of single atoms. Comparative measurements between metal and rare gas clusters are discussed.

[1] T. Döppner et al., Phys. Rev. Lett. 94:013401, 2005

[2] T. Döppner et al., Phys. Rev. A 73:R031202, 2006

[3] Th. Fennel et al., Eur. Phys. J. D 29:367, 2004