Objective:
Study of plasma-dust crystals and liquids under microgravity conditions.

Used science hardware:
• Apparatus PK-3 Plus;
• Videoapparatus Telescience.

Description of the experiment:
During the experiment, working chamber of apparatus PK-3 develops plasma of high-frequency discharge with specified parameters. Dust particles of the required size are injected into plasma; videorecording of generating plasma-duct structures is performed with different plasma parameters. Video images are transmitted to earth if necessary via the ISS RS TV system, as well as downloading of digital data by telemetry channels.

Experiment results:
For the first time it was found that there were formed three-dimensional ordered structures of micron-size heavily charged particles with a large parameter of imperfection (three-dimensional plasma crystal) with face-centered and body-centered lattices. It was shown that face-centered and hexagonal structures could coexist simultaneously. Excitation of dust component waves was performed, which makes it possible to obtain dispersion rations and study wave pattern. Nonlinear waves of dust component density were found. Areas with convective motion of charged macroparticles in liquid plasma ("plasma-dust vortices") were revealed; in so doing, particle behaviour differs significantly from that being observed under gravity conditions. A possibility was demonstrated to study macroparticle growth from gas phase under microgravity conditions.