München 2004 – wissenschaftliches Programm
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A: Atomphysik
A 16: Multiphotonionisation I
A 16.1: Vortrag
Donnerstag, 25. März 2004, 14:00–14:15, HS 133
Ionisation dynamics in the transition regime between non-relativistic and relativistic laser intensities — •Elena Gubbini1, Ulli Eichmann1,2, and Wolfgang Sandner1,2 — 1Max Born Institute, Max-Born-Strasse 2a, 12489 Berlin — 2Technical University Berlin, D-10623 Berlin
For a better understanding of the physical processes that are playing a role during a short pulse laser-atom interaction, an interesting investigation is the ionisation of rare gases at ultra-strong laser intensities in the transition regime between a non relativistic and a fully relativistic treatment of the electron dynamics (1016 W/cm2 to 1018 W/cm2). Here, the ionised electrons are not yet relativistic, but it can be shown that the influence of the magnetic field component is no more negligible.
We have investigated the intensity dependent ionisation yields for highly charged states of different rare gases (i.e., Nen+; n = 6,7,8). Comparison of the experimental data with a theory based on tunneling (ADK-theory) suggests that dominant ionisation occurs via a sequential process. A classical calculation of the trajectories of an electron in an electro-magnetic field (F=q(E+v× B)) confirms that already for intensities that are not yet relativistic, the magnetic field influences the rescattering of the electron. It reduces the non-sequential ionisation observable otherwise at laser intensities below 1016 W/cm2.