Complex plasma laboratory PK-3 Plus on the International Space Station

PK-3 Plus is the second-generation laboratory for the investigation of complex plasmas under microgravity conditions on the International Space Station (ISS). It has more advanced hardware, software and diagnostics than its precursor PKE-Nefedov (Nefedov et al 2003 New J. Phys. 5 33). The first experiments with PK-3 Plus show the perfect functioning of the apparatus and provide much better insights into the properties of complex plasmas. In particular, the 'void' in the center of the complex plasma cloud can now be easily closed, thus providing a much better homogeneity of the complex plasma—a feature which was hardly achievable before—but which is essential for many precision studies. Moreover, the use of the function generator at frequencies above the dust plasma frequency provides many possibilities for future experiments. Other interesting phenomena are related to high densities of the microparticles in the complex plasma. These so-called heartbeat and filamentary mode instabilities can be investigated in detail, by comparing particle motion with the discharge glow characteristics.