Complex Plasma under Microgravity: Utilizing the International Space Station Plasma Krystal-4 Facility and Beyond

Auburn University, Auburn AL

Investigators

Abstract

This award will support the analysis of data and a series of dedicated experiments on the International Space Station (ISS) aimed at understanding fundamental properties of the complex plasma systems. Plasmas have long been studied in the astrophysical setting since most of the universe is in a plasma state and are important in explaining the live cycles of stars. The heavy use of plasma production methods in the semiconductor industry also demonstrates the economic importance of plasma based production methods in our society. In nearly all situations were plasmas exist, small particles may be embedded in the plasma environment either as a natural component, as a result of unintended growth from chemical reactions, or introduced intentionally. The presence of the dust particle component can significantly change the overall behavior and the properties of the plasma. In some cases, the presence of the dust can have negative effects such as significant yield reductions in processing plasma manufacturing or undesired complications in the design of fusion devices. On the other hand, the presence of the dust can also result in new plasma production methods and provides an accessible, excellent model system to investigate the universal behavior and properties of general complex particle systems. The full potential of the complex plasma research requires that some experiments be performed under reduced gravitational influence, as provided by the ISS. This award will support the training of the next generation of highly qualified scientists and engineers by providing the opportunity to work with a team of international collaborators. The investigators will make use of the recently developed microgravity complex (dusty-) plasma facility Plasma Krystal-4 (PK-4), which is a European-Russian apparatus now on the International Space Station. Working in a close collaboration with the European core team of PK-4 scientists, the US team will study fundamental aspects of complex plasma including the charging and interaction of individual particles, particle transport and the thermal properties of the overall system. These fundamental interactions between the particles in a complex plasma is the basis for understanding its overall behavior. For example, increasing the strength of the interaction relative to the random motion can cause the system to undergo a transition from an irregular, uncorrelated (liquid) state to an ordered, crystalline structure (solid). Using experimental data obtained from the PK-4 experiment, the charging and particle pair interaction will be studied by examining the dynamics of individual particles during pair collisions. Particle transport and heating of particles will be examined using additional experimental data obtained from the PK-4 experiment and results from dedicated ground based experiments. Required software tools to follow the motion of individual particles (particle tracking velocimetry) and the overall particle flow (particle image velocimetry) will be developed. A series of experiments to support the development of potential future microgravity complex plasma experiments will also be performed. This award to support an undergraduate student is made under a "NASA/NSF Partnership on Science of Dusty Plasmas: Utilizing the PK-4 Facility on board the International Space Station" and is complementary to a NASA award made under the joint program.