Powder particles have been used, for instance, as micro-probes for the determination of the electric field in front of electrodes and substrates, as well as for the observation of energy fluxes between plasma and surfaces. By observing the position and movement of the particles dependent on the discharge parameters, we obtained information on the electric field in front of the electrode to be in the order of 350 V/m. For this purpose an adapted model has been employed for determining the dust charge, which in our case was of the order of 7000e. The equilibrium temperature of the particles, which is a result of the different energy fluxes from the plasma, has been determined by temperature-dependent fluorescence of the micro-particles to be of the order of 100-200 degreesC. In case of an argon plasma the heating of the particles by charge carrier recombination could be identified as dominant energetic contribution, while the losses are due to radiation and conduction. The energy flux towards the particles is approximately 0.1 J/cm(2)s.