The most obvious example of this kind of research can be found at the Max Planck Institute for Plasma Physics (IPP) in Greifswald. The main focus of the research carried out at this institute of the Max Planck Society is on nuclear fusion. This approach is based on the vision of enabling the energy-generating processes that take place in the sun, that is the fusion of light atomic nuclei, for example deuterium and tritium, to heavier nuclei such as helium, to take place under terrestrial conditions and thereby operate power plants using the energy released by this process. Although the associated reactor systems are already under construction, at present, numerous fundamental problems remain to be resolved. In a fusion experiment, extremely hot plasma must be confined, and a magnetic field is the only possible means of achieving this. The magnetic field can be designed on the basis of two different principles. The main approach that has been adopted up to now is the so-called tokamak principle, in which the plasma current flows in toroidal paths in a magnetic field and is confined in this way. The stellarator is an interesting alternative to the tokamak, in which a very complex magnet field ensures that the plasma is confined without a current being driven through the plasma itself.
The considerable advantage of the stellarator principle is that it enables continuous operation whereas, without additional effort and expense, a tokamak can only be operated in pulse mode. The currently most technologically advanced nuclear fusion system, the planned international ITER project, involves the construction of a tokamak, as this would appear to be easiest to complete. The IPP is one of the central research institutes involved in the construction of the ITER reactor. However, work is also being carried out by the Max Planck Society in Greifswald on the Wendelstein 7XExperiment, which is by far the world’s most ambitious stellarator experiment. Before such reactors are ready for use, answers must be found to fundamental questions regarding the optimal way of confining plasma in such magnetic fields. Thanks to the extensive freedom and scope they allow researchers in their work, the Max Planck Society’s structure enables approaches to be developed in parallel to the mainstream that could result in the establishment of even better solutions in the distant future.
Along with the construction of such reactors and the implementation of the associated experiments, numerous extremely complex basic issues must be resolved to ensure that we will really be able to rely on nuclear fusion as one of our main energy sources in the future. These include, for example, the development of suitable material to line the wall of fusion reactors, as the plasma contact in such a reactor is one of the heaviest uses that any material can be subject to under terrestrial conditions.