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Abstract Complex plasma is a state of soft matter where micrometer-sized particles are immersed in a weakly ionized gas. The particles acquire negative charges of the order of several thousand elementary charges in the plasma, and they can form gaseous, liquid and crystalline states. Direct optical observation of individual particles allows to study their dynamics on the kinetic level even in large many-particle systems. Gravity is the dominant force in ground-based experiments, restricting the research to vertically compressed, inhomogeneous clouds, or two-dimensional systems, and masking dynamical processes mediated by weaker forces. An environment with reduced gravity, such as provided on the International Space Station (ISS), is therefore essential to overcome this limitations. We will present the research goals for the next generation complex plasma facility COMPACT to be operated onboard the ISS. COMPACT is envisaged as an international multi-purpose and multi-user facility that gives access to the full three-dimensional kinetic properties of the particles.
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Electric field driven aggregation of negatively and positively polarized particles in dilute suspensions.
A variety of colloidal structures observed in terrestrial experiments could also have been influenced by gravity effects (particle sedimentation, convection, etc.) It is often assumed that weightlessness simulated in a time-averaged sense by slowly rotating a specimen in a clinostat about an axis perpendicular to the gravity direction that is widely used in biological tests would reduce the effect of gravity on suspensions. Experiments on a non-buoyancy-matched suspension in flights in NASA Zero-gravity aircraft revealed that particle patterns formed in a clinostat and under normal gravity are actually similar. A requirement for matching densities between particles and a solvent severely limits possibilities to study the field-induced structuring in colloids in terrestrial experiments. Long-term microgravity in ISS offers unique opportunity to employ not density matched suspensions to explore a wide range of the mismatch of electric characteristics between particles and a solvent. We will report experimental data on the field driven structure formation in suspensions and present our approach to the development of ISS experiments. The aim is to understand mechanisms of structure formation and suggest novel routes for creating functional materials. *NASA NNX13AQ53G, NSF1832260.
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- Award ID(s):
- 1832260
- PAR ID:
- 10186151
- Date Published:
- Journal Name:
- Bulletin of the American Physical Society
- Volume:
- 65
- Issue:
- 1
- ISSN:
- 0003-0503
- Page Range / eLocation ID:
- J31.00005
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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