Berlin 2001 – wissenschaftliches Programm

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P: Plasmaphysik

P VI: HV VI

P VI.1: Hauptvortrag

Mittwoch, 4. April 2001, 15:30–16:00, 2053

Laser Manipulation of Particles in Complex (Dusty) Plasmas — •Andre Melzer — Institut für Experimentelle und Angewandte Physik, Christian-Albrechts-Universität Kiel, 24098 Kiel, Germany

Complex (dusty) plasmas contain charged macroparticles (nanometer to micrometer size) immersed in a plasma environment of electrons, ions and neutrals. The particles attain a negative floating potential that results in a high negative charge on the particles of the order of several thousand elementary charges. The Coulomb interaction potential of the particles by far exceeds their thermal energy, the particles are said to be strongly coupled.

Due to the large size of the particles and the involved time scales in complex plasmas dynamic processes can be investigated on a kinetic microscopic level. This makes complex plasmas an ideal system linking the fields of plasma physics and condensed matter.

Focused laser beams are a versatile tool for manipulation of individual particles in complex plasmas. This technique allows quantitative determination of the key properties of complex plasmas, such particle charge, screening strength and interaction potentials. Experiments on laser excitation of waves, Mach cones, normal modes and oscillations are presented. In addition, the laser technique allows to reveal the unusual formation of attractive forces between the negatively charged particles.