Stuttgart 2012 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 19: Komplexe und staubige Plasmen

P 19.6: Vortrag

Donnerstag, 15. März 2012, 15:40–15:55, V57.02

Laser heating of finite 2d dust clusters: Simulation results — •Hauke Thomsen, Hanno Kählert, and Michael Bonitz — ITAP, Christian-Albrechts-Universität zu Kiel, Leibnizstr. 15, 24098 Kiel

When investigating the temperature behavior of dust clusters, it is essential to have selective control over the dust temperature. Using several laser beams, the dust particles are accelerated due to the momentum transfer by the radiation pressure[1]. The great advantage of this technique is that plasma parameters like temperature, pressure and screening length remain unaffected. A central question is how to achieve a homogeneous heating effect. We performed Molecular Dynamics simulations where the laser spots were implemented as time and space dependent forces. In collaboration with J. Schabliski et. al. from the experimental group of Prof. Piel, we could show that a heating method that uses two pairs of laser beams in perpendicular direction meets all demands[2,3]. Therefore, the spatial cluster structure as well as the velocity distribution were investigated. The spectral analysis showed, that when the lasers are driven with constant frequencies, these frequencies appear as peaks in the velocity power spectrum. On the other hand, randomly changing the laser scanning frequencies with time avoids these effect. As a result, we found a method that is well appropriate to heat a dust cluster without affecting the surrounding plasma and without artifacts from the method.

[1] V. Nosenko and J. Goree, Physics of Plasmas 13, 032106 (2006) [2] J. Schabliski et al., Physics of Plasmas (2012) [3] H. Thomsen et al., Physics of Plasmas (2012)