Entropy Measurement in Strongly Coupled Complex Plasmas

The change in entropy of a system that is transferred between two states at different temperatures is measured in a two-dimensional plasma crystal experiment. One- and especially two-component dust clusters are confined in the plasma sheath and heated to different temperatures using laser manipulation. We find that entropies obtained from the phase space yield consistent results for, i.e., the heat capacity which shows excellent agreement with the Dulong-Petit law. The implications for the validity of basic thermodynamical principles in finite size complex (dusty) plasmas are discussed.