Tuesday, January 24, 2017

Vertical oscillations of dust particles in a strongly magnetized plasma sheath induced by horizontal laser manipulation

M. Puttscher, A. Melzer, U. Konopka, S. LeBlanc, B. Lynch, and E. Thomas Jr.

Experimental studies are presented where dust particles are suspended in the lower sheath region of an argon rf discharge at a strong vertical magnetic field from B=1.5B=1.5 T up to 2.272.27 T. There the particles arranged in an ordered pattern imposed by the upper mesh electrode. It is observed that the particles jump to a new equilibrium position, where they exhibit self-excited vertical oscillations when illuminated by a horizontal laser beam. The dust motion is weakly damped during an upward jump and strongly damped during the return to the equilibrium after the laser is switched off. A model based on delayed charging is presented that can describe the observed behavior.

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