Plasma inhomogeneities near the electrodes of a capacitively- coupled radio-frequency discharge containing dust particles

Small plasma spheroids are evidenced and analyzed in front of the electrodes of a capacitivelycoupled radio-frequency discharge in which dust particles are growing. These regions are characterized by a spherical shape, a slightly enhanced luminosity and are related to instabilities induced by the presence of dust particles. Several types of behaviors are identified and particularly their chaotic appearance or disappearance and their rotational motion along the electrode periphery. Correlations with the unstable behavior of the global plasma glow are performed. These analyses are obtained thanks to high-speed imaging which is the only diagnostics able to evidence these plasma spheroids.