The heart of the PK-3 Plus laboratory consists of a
capacitively coupled plasma chamber. A
plasma is generated by applying a
radio frequency voltage signal to two electrodes.
Microparticles are then injected into the plasma via dispensers that are mounted on the side of the electrodes. The microparticles are illuminated with a sheet of
laser light from the side. They scatter the light, which is then recorded by up to four cameras mounted around the plasma chamber. The data from the cameras are recorded on hard drives that are physically brought back to Earth via
Soyuz capsules for analysis.
Scientific goals
PK-3 Plus studies complex plasmas - plasmas that contain
microparticles. The microparticles acquire high negative charges by collecting electrons from the surrounding plasma. They interact with each other and with the plasma particles, e.g., they experience a
drag force from the ions that are streaming to the edges of the plasma.
Depending on the experimental settings like the gas pressure, the system made up of the microparticles forms various
phases -
solid,
liquid or
gaseous. In this sense, the microparticles can be seen as analogous to atoms or molecules in ordinary physical systems. The experiments are performed by observing the movement of the microparticles and tracing them from camera frame to frame.
^Heidemann, R. (2011). "Comprehensive experimental study of heartbeat oscillations observed under microgravity conditions in the PK-3 Plus Laboratory on board the". Physics of Plasmas. 18 (5): 053701.
Bibcode:
2011PhPl...18e3701H.
doi:
10.1063/1.3574905.