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Highly-charged ion dynamics

In the interior of stars, around galactic cores and black holes, temperatures of millions of Kelvins are prevailing. Galaxy clusters are enclosed in an extremely dilute, but similarly hot plasma medium; both galaxies and plasma are held together by the gravitational action of the present Dark Matter. In these environments, atoms are in very high positive ionization states, but can absorb and emit radiation with their remaining bound electrons. The spectral lines of such “highly charged ions” are very import in astrophysics, because they come from the hot Universe. In our laboratory, we produce such ions, store them for long time spans, and investigate their spectra from the x-ray to the visible range. Furthermore, we can excite them with lasers and x-ray lasers, or can cool them down to temperatures close to absolute zero. We are developing experiments and techniques to scrutinize the laws of physics to their limits over a temperature range of 12 orders of magnitude: Is it possible to design atomic clocks based on highly energetic photons, where atoms fail but highly charged ions do not? Are fundamental constants of nature perfectly constant? Where can atomic structure theory be improved? Do we understand astrophysical data correctly?