More plasma research is being conducted on the International Space Station (ISS). From 10 to 16 November 2019, the Russian cosmonaut Alexander Skvortsov will be carrying out a new series of experiments with the PK-4 plasma crystal laboratory. Under the direction of scientists from the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR), Skvortsov will record how microparticles move through a neon plasma in microgravity, forming structures and thus providing insights into basic physical processes.
The scientists are following the experiments with interest from the CADMOS control centre in Toulouse, France. The cosmonaut's most important task is to start the measurements at the correct moment, by sending the microparticles through the ionised gas and capturing the movements of the 'complex plasmas' on the monitor. Skvortsov already has a certain amount of practical experience, as he is currently completing his third long-term stay on board the ISS. During his first mission, in 2010, he carried out plasma crystal experiments with the predecessor laboratory, PK-3 Plus, as part of a German-Russian collaboration. The current PK-4 laboratory has been installed in the European Columbus module on the ISS and, as a multipurpose multi-user facility, offers a wide range of possibilities for plasma research under microgravity conditions.
The main objective of the DLR Complex Plasmas Research Group is to acquire knowledge that will appear in the textbooks of the future. Plasma crystal experiments reveal the dynamics of liquids and solids as a model system. This fundamental research is also important for understanding complex plasmas, which have been found to be a distinct physical state of soft matter – through experiments conducted in space. There are also naturally-occurring complex plasmas, known as 'dusty plasmas'. These can be found in lightning that occurs during volcanic eruptions, for example, and can be artificially generated in the laboratory. This provides fundamental knowledge that may be important for fusion plasmas, and also for exploration missions to the Moon or Mars.
Physics research in microgravity is one of the key topics at the DLR Institute of Materials Physics in Space, which is based in Cologne. The Institute conducts various experiments relating to materials research in metals, alloys and soft matter – in colloidal physics, granular matter and complex plasmas – on parabolic flights, in the drop tower, on sounding rockets and on board the ISS. These activities are accompanied by experimental and theoretical research work on Earth, as well as numerical simulations. With over 100 scientific publications since the programme started in 2001, the plasma crystal experiments have been among the most successful research work ever to take place on the ISS.