We report on experimental observations of large amplitude dust acoustic oscillations and transverse shear waves in a three dimensional configuration of dusty plasma that is in the strongly coupled fluid regime. The onset and nature of these spontaneous oscillations is strongly influenced by the ambient neutral pressure. In an extended dust cloud, as the neutral pressure is progressively diminished, spontaneous longitudinal oscillations appear first followed by transverse shear waves. For more compact equilibium configurations the shear waves do not appear but a further decease in pressure causes the dust acoustic waves to develop higher harmonic oscillations. A simple theoretical model based on the generalized hydrodynamic (GH) equations is developed to explain this phenomena.
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