This research seeks advancement of the basic knowledge of the physics of dusty plasmas (one of the fast growing areas of plasma physics), and its application to diverse environments such as the Earth's ionosphere, and laboratory and industrial plasmas. Areas of study include: (1) waves and instabilities in weakly coupled dusty plasmas, including effects such as magnetic fields, plasma inhomogeneities and boundaries, with detailed applications to dusty plasmas in the Earth's ionosphere and in the laboratory; (2) waves and structures in strongly coupled dusty plasmas, including waves in bilayers, and lattice structures of paramagnetic dust. (3) innovative applications involving interaction with electromagnetic waves.
The proposal covers a broad range in that it investigates the basic physics of various dusty plasma environments, including space and laboratory dusty plasmas in magnetic fields, strongly coupled dusty plasmas, dust in microplasmas, and possible technological applications of dusty plasmas.
The research includes training of students and broad dissemination of results through talks and publications. In addition, the research may have impacts on plasma technologies (e.g., plasma processing, nuclear fusion) in which dusty plasma concepts can play a role. Furthermore, some of the research may have overlap with topical research areas in photonics technology (e.g. photonic crystals).
This proposal was submitted to the NSF-DoE Partnership in Plasma Science and Engineering joint solicitation 08-589. This award is being funded by the Plasma Physics Program in the Division of Physics.
We conducted theoretical studies in the physics of dusty plasmas. Dusty plasmas are ionized gases containing electrons, ions, neutral atoms and small charged solid particulates, or dust grains. Dust occurs in cosmic environments, such as Saturn's rings, comets, noctilucent clouds in the Earth’s mesosphere, and star-forming regions in interstellar space. Dust can also occur in terrestrial plasmas, such as industrial plasmas used for semiconductor manufacturing. Over the last two decades, dusty plasmas have been studied in dedicated laboratory experiments where typically micron sized grains are used. The dust grains can be multiply charged, are orders of magnitude more massive than the ions, and can act as a heavy charged component of the plasma. In laboratory experiments the dust can also be strongly coupled (i.e., the potential energy between neighboring grains exceeds their kinetic energy), resulting in liquid or crystalline behaviors that are similar to physical processes in condensed matter, but on a macroscopic scale that facilitates observation. Our theoretical research has focused primarily on the collective behavior of dusty plasmas. This includes the study of waves and instabilities, as well as effects of strong dust coupling. The intellectual merit of our research is the advancement of the basic knowledge of the collective physics of dusty plasmas, along with applications to space and the laboratory. We worked on a broad range of topics, in order to compare theory with experiments or observations, and to motivate new experiments in this rapidly developing field. Our research results have been reported in 22 scientific publications in peer-reviewed journals. Among the topics we studied were: (i) charging of mesospheric dust, (ii) instabilities that can help explain observations of certain waves in dusty plasma and negative ion plasma experiments, (iii) conditions for exciting various types of waves in forthcoming dusty plasma experiments with large magnetic fields, (iv) effects of strong coupling on instabilities driven by particle flows in dusty plasmas and ultracold neutral plasmas, (v) predictions of tunable crystalline structures in dusty plasmas composed of paramagnetic grains, and (vi) innovative possible applications of dusty plasmas such as the selective absorption of infrared radiation. The broader impacts of the project include the training of students: at UCSD, a graduate student and an undergraduate student were involved in aspects of the research.
