Plasma Kristall 4 (PK-4)
PK-4 is a scientific laboratory-style payload for performing research in the field of 'Complex Plasmas'. These are low-temperature gaseous mixtures composed of ionized gas, neutral gas and micron-sized particles. The micro-particles become highly charged in the plasma and interact strongly with each other through the Coulomb force.
These interactions can, in specific conditions, lead to a self-organized structure of the micro-particles: so-called plasma crystals. PK-4 will consist of a glass-made DC discharge plasma chamber.
The elongated DC-plasma chamber of PK-4 is especially suited for investigations of complex plasmas in the fluid phase, e.g. transition from laminar to turbulent streaming on the microscopic level. On ground such experiments are distorted by gravity or even impossible.
The science objectives of PK-4 include the study of:
Transport Properties: Dust Diffusion, Hydrodynamics (viscosity), and Heat Transfer
Thermodynamics: Thermodynamic Functions, Phase Transitions, Structures, Two- and Three Particle Correlations
Kinetics and Statistical Physics: Charging and Forces, Integral Equations, Statistical Modelling for Strongly Coupled Systems
- Non-linear waves and Instabilities
PK-4 experiment apparatus
Plasma chamber (glass, ~45 cm in length, 3 cm in diameter), vacuum pump, gas filling system, particle dispensers, DC high voltage supply, RF-generator, diagnostics (illumination, cameras, data storage), manipulation laser, thermal manipulator (heating element attached to glass plasma tube) and electromagnetic manipulator (DC electrode inside glass plasma tube).
Current status of development
Since 1998, prolonged experiments with complex plasmas have taken place in space: first, on the Russian Mir space station as part of the Russian programme, then on the ISS, as part of a German-Russian collaboration. ESA is building the next generation of complex plasma experiments for the ISS: PK-4.
Phase C/D has started in September 2008.
Last update: 13 May 2009