Strongly-Coupled Dusty Plasmas

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This project is a fundamental experimental study of waves, transport, nonequilibrium fluctuations, and viscoelastic behavior in strongly coupled dusty plasmas. Strongly coupled plasmas are ionized gases in which the interparticle potential energy is greater than the particle kinetic energy. They behave like a crystal or liquid, unlike the more familiar weakly coupled plasmas, which behave like a gas. A dusty plasma is a four-component mixture of micron-size particles of solid matter, electrons, ions, and neutral gas. The solid particles become charged due to collecting electrons and ions. The electric field in a plasma sheath can levitate these charged particles against gravity, allowing the confinement of 1D, 2D or 3D clouds of particles. A particle's charge is large, typically Q = -10,000 electronic charges, so that pairs of particles have a large interparticle repulsion. The large potential energy of this repulsion, together with a cooling of particles by gas drag, lead to strong coupling among the particles. By tailoring the manipulation and confinement of the particles, experiments are performed to study a variety of physical phenomena in statistical mechanics, transport and nonlinear waves. The broader impact of this project includes: cross-cutting research topics of interest to a wide range of physics disciplines, outreach, training of graduate and undergraduate students, and broad dissemination of results.