  An algorithm has been developped, which makes it possible to automatically
extract trajectories of a large number of particles from fast imaging data,
allowing a statistical analysis of particles trajectories under various plasma
conditions, a better understanding of their influence on plasma properties, and
a better characterization of the plasma itself. In this contribution, we focus
on results obtained in a radiofrequency parallel plate reactor, where a large
amount of micron-sized carbon dust is produced in situ. The use of the rescaled
range analysis (R/S analysis) applied to dust particles displacements allows
decomposing dust dynamic on different time scales. It is shown that dust
displacement is dominated by collisions on short time scales whereas long term
behaviour is strongly influenced by large scale plasma fluctuations.
