Microparticles in plasmas as diagnostic tools and substrates

An interesting aspect in the research of complex (dusty) plasmas is the experimental study of the interaction of nano- and micro-particles with the surrounding plasma for diagnostic purpose. From the behaviour of the particles, local electric fields can be determined ("particles as electrostatic probes"), the energy fluxes towards the particles ("particles as thermal probes"), or reactive processes on surfaces ("particles as micro-substrates") can be studied. The behaviour of particles in front of an adaptive electrode, which allows for an efficient confinement and manipulation of the grains, has been experimentally studied in dependence on the discharge parameters and on different bias conditions of the electrode. The effect of the biased surface on the charged micro-particles has been investigated by novel particle falling experiments, which were observed by a fast camera. Furthermore, preliminary experiments on the excitation of whispering gallery modes of micro-particles trapped in a plasma sheath have been demonstrated for the first time.