Measurements of the power spectrum and dispersion relation of self-excited dust acoustic wavesV. Nosenko1, S. K. Zhdanov1, S.-H. Kim2, J. Heinrich2, R. L. Merlino2 and G. E. Morfill1
1 Max-Planck-Institut für extraterrestrische Physik - D-85741 Garching, Germany, EU
2 Department of Physics and Astronomy, The University of Iowa - Iowa City, IA 52242, USA
received 1 September 2009; accepted in final form 25 November 2009; published December 2009
published online 4 January 2010
The spectrum of spontaneously excited dust acoustic waves was measured. The waves were observed with high temporal resolution using a fast video camera operating at 1000 frames per second. The experimental system was a suspension of micron-size kaolin particles in the anode region of a dc discharge in argon. Wave activity was found at frequencies as high as 450 Hz. At high wave numbers, the wave dispersion relation was acoustic-like (frequency proportional to wave number). At low wave numbers, the wave frequency did not tend to zero, but reached a cutoff frequency instead. The cutoff value declined with distance from the anode. We ascribe the observed cutoff to the particle confinement in this region.
52.27.Lw - Dusty or complex plasmas; plasma crystals.
52.27.Gr - Strongly-coupled plasmas.
52.35.Fp - Electrostatic waves and oscillations (e.g., ion-acoustic waves).
© EPLA 2009