Complex (dusty) plasmas consist of mesoscopic grains immersed in the background of a gaseous plasma of electrons, ions and neutral atoms. The grains become highly charged, collecting electric charges up to 10000 times the electronic charge and acquiring a high level of potential energy. As a result, they become strongly coupled, i. e. their dynamics becomes governed by their potential, rather than their kinetic energy. In this state, the behavior of the grains largely mimics, albeit on a different scale, many of the physical processes that atoms and molecules undergo in condensed matter. This project addresses the dynamical behavior of complex plasmas through theoretical analysis combined with computer simulation. As such, it represents a novel approach to problems associated with issues in areas of condensed matter physics, by studying processes similar to those occurring in solids, liquids, etc. on a "magnified" scale where direct visual observation is possible. This approach requires that the investigators possess a broad overview of many different areas of physics. A special intellectual merit of the project is the use of a unique analytic method, created some time ago by the Principal Investigator and his colleagues, This method, referred to as the Quasi Localized Charge Approximation, was already tested in earlier funding periods where it provided interpretations of a variety of laboratory experiments and computer simulations.
Complex (dusty) plasmas occur in a variety of natural situations. Examples are various astrophysical systems, the Earth's environment, gas discharges, semiconductor processing facilities, etc. In addition, laboratory experiments and experiments in gravitation free environment in the orbiting Space Station produce these strongly coupled plasmas as well: from the experimental point of view these systems are unique in that they combine properties of conventional plasmas and (liquid and solid) condensed matter. This is a key feature that provides the opportunity to study properties of various highly dissimilar physical system, such as colloids, stellar interiors, magnets, cryogenic "ultracold" systems and extremely hot and dense matter created in particle accelerators under macroscopic "visible" experimental conditions. The major computer simulation program of the project will open broad opportunities for students in training and practicing in computational methods. Participating students will be encouraged to visit US and overseas laboratories and training programs.