Characteristics of dusty plasma instabilities: Pressure and power dependences
Résumé
When a huge density of dust particles is grown inside a plasma, low frequency instabilities can appear due to a change in the plasma electrical equilibrium. These instabilities are characterized by their apparition time, duration and frequency evolution and show a well-defined succession of phases. All these characteristics are dependent of the dust particle growth kinetics that depends of the discharge parameters. In this contribution we show the influence of the gas pressure on the main instability properties. In addition, we present high-speed imaging analyses showing the existence of localized plasma spheroids during the instabilities. The spheroid behaviour appears to be modified by the rf power that changes the spheroid rotation speed around the electrode.