Erlangen 2018 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 22: Complex Plasmas and Dusty Plasmas - Poster

P 22.3: Poster

Mittwoch, 7. März 2018, 16:15–18:15, Zelt West

Mach cones in inhomogeneous plasma crystals — •Sven Werner Schmidt, Frank Wieben, and Dietmar Block — Institute of Experimental and Applied Physics, Kiel University, Germany

Complex plasmas are ideal systems to study wave phenomena in strongly coupled system at the kinetic level. The sound speed of dust acoustic waves depends on charge-to-mass ratio and screening strength κ. The Mach cones which are generated by a supersonic perturbation can thus be used as a diagnostic tool. Most experiments and simulations investigate Mach cones only in the central parts of a 2D crystal where a homogeneous density is assumed. This contribution investigates Mach cones in inhomogeneous media. Especially for small dust systems the parabolic confinement yields to a notable radial density gradient. In order to correctly measure q/m or κ in an inhomogeneous system it is essential to analyse the Mach cone shape. Mach cones in a plasma crystal are excited by a moving laser beam. Using a model for Mach cone curvature in inhomogeneous media [1] a reliable measurement of the sound speeds is shown to be possible.

This work was supported by the Deutsche Forschungsgemeinschaft DFG in the framework of SFB TR24 Greifswald Kiel, Project A3b and of Research Grant BL555/3-1.

[1] S.K. Zhdanov et. al., Phys. Rev. E 69, 026407 (2004)