Göttingen 2025 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 12: Complex Plasmas and Dusty Plasmas I

P 12.3: Vortrag

Mittwoch, 2. April 2025, 11:45–12:00, ZHG006

Bow shock formation in a dusty plasma flowing around an obstacle under microgravity — •Stefan Schütt, Christina Knapek, Daniel Maier, Daniel Mohr, and André Melzer — University of Greifswald, Greifswald, Germany

Dust flows around an obstacle in three-dimensionally extended dust clouds have been investigated on parabolic flights. As the obstacle, a tungsten wire has been installed in the midplane between the electrodes of a parallel plate radio-frequency discharge. A periodic dust motion was generated by superimposing a low-frequency modulation on the electrodes, shifting the dust cloud between the electrodes. Due to the periodic nature of the dust motion, several shocks could be observed at varying dust densities. When the dust flow was transonic or supersonic, bow shocks were formed upstream of the wire and propagated away from it at a constant speed. However, at the dust densities needed for the shock formation, dust-density waves also occurred and the two phenomena often intermingled. The role of the streaming ions in driving the shock is therefore discussed. At carefully chosen parameters, it was possible to observe only the bow shock while suppressing the waves. It is reasoned that the shock is excited independently from dust-density waves by a density increase upstream of the obstacle.

This work was supported by DLR grants 50WM1962 and 50WM2161.

Keywords: dusty plasma; parabolic flight; dust flow; bow shock