GREMI, Groupe de Recherches sur l’Energétique des Milieux Ionisés, UMR 6606, CNRS/Université d’Orléans, 14 rue d’Issoudun, BP6744, 45067 Orléans Cedex 2, France
Small plasma spheroids are evidenced and analyzed in front of the electrodes of a capacitively-coupled 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.
(Received April 15 2011)
(Revised July 25 2011)
(Accepted August 03 2011)
(Online publication October 28 2011)
p1 Present address: Laboratoire de Physique des Interactions Ioniques et Moléculaires, UMR 6633 CNRS/Université de Provence, 13397 Marseille, France