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P: Plasmaphysik

P 28: Astrophysikalische Plasmen; Dichte Plasmen 1; Schwerionen- und lasererzeugte Plasmen 2; Staubige Plasmen 4; Theorie 1

P 28.18: Poster

Wednesday, March 29, 2006, 17:30–19:00, Flure

Particle charge measurements in 3D dust crystals. — •Yuriy Ivanov and Andre Melzer — Institut fuer Physik, Ernst-Moritz-Arndt-Universitaet Greifswald

The physics of dusty plasma has attracted a growing interest in the last years. Particles immersed and confined in a laboratory plasma usually form 2D dust crystals. Very recently, spherical 3D coulomb clouds have been generated in laboratory experiments [1]. To levitate particles in the plasma bulk thermophoretic forces have been used. The charge of particles in such 3D crystals has been investigated. The usual charge measurement methods for 2D dust crystals base on the investigation of dynamical properties (resonance and normal mode methods). They are much more difficult to investigate in 3D crystals due to two main reasons: first, due to necessity of simultaneous determination of a series of 3D particle trajectories. The second reason is related to the fact that stable 3D Coulomb balls can be generated only at high gas pressure which implies strong damping of the dynamic properties. Nevertheless, we use laser manipulation techniques and normal mode analysis to study the charge and confinement of the dust particles in a Coulomb ball. The obtained results will be compared with simulations of the dust clouds.

Supported by DFG under SFB TR24, project A3.

[1] O. Arp, D. Block, A. Piel and A. Melzer, "Dust Coulomb balls: Three-Dimensional Plasma Crystals", Phys. Rev. Lett. 93 (2004) 165004