Hannover 2016 – wissenschaftliches Programm
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A: Fachverband Atomphysik
A 11: Atomic clusters I (with MO)
A 11.6: Vortrag
Montag, 29. Februar 2016, 18:15–18:30, f107
Ionization avalanching in clusters ignited by extreme-ultraviolet driven seed electrons — •Mathias Arbeiter1, Bernd Schütte2, Alexandre Mermillod-Blondin3, Marc J. J. Vrakking3, Arnaud Rouzée3, and Thomas Fennel1 — 1University of Rostock, Germany — 2Imperial College London, United Kingdom — 3Max-Born-Institut, Berlin, Germany
Nanoplasma formation in rare-gas clusters under intense near-infrared (NIR) fields is triggered by atomic tunnel ionization. Subsequently, the ionization dynamics is dominated by impact ionization avalanching, efficient heating via inverse Bremsstrahlung (IBS), and resonant collective plasmon excitation. This ionization ignition, however, requires high intensities to reach the tunnelling threshold [1].
Recent experiments show that a few photo-activated seed electrons from an additional weak XUV pulse allow the control of ionization avalanching [2]. In this two-color scenario, highly charged ion emission occurs at NIR intensities far below the tunnel ionization threshold and is switched by the XUV field. We studied the XUV-induced nanoplasma formation as well as its subsequent NIR-driven evolution by molecular dynamics simulations. We find that avalanching starts with even very few seed electrons and that resonance effects are crucial to explain the observed ion emission. Further, our results support that the XUV-NIR scenario might enable the so far unprecedented investigation of IBS at low ponderomotive potentials.
[1] Rose-Petruck et al., Phys. Rev. A 55:1182 (1997).
[2] B. Schütte et al., arXiv:1509.03250 (2015)