In the fall of 2015, the Ruhr Astroparticle and Plasma Physics Center (RAPP Center) was founded in order to combine research efforts within the fields of plasma, particle, and astrophysics in the Ruhr area. The three universities Ruhr-Universität Bochum, Technische Universität Dortmund, and Universität Duisburg-Essen are located within a radius of 20 kilometers, enabling close collaboration between the universities. Founding principal investigators (PIs) of the RAPP Center are Prof. Wurm (Duisburg-Essen), Professors Dettmar, Schlickeiser, and Tjus (all Bochum), as well as Professors Rhode and Spaan (both Dortmund). In June 2017, the center was expanded, now combining research activities of 23 PIs from the areas astro-, particle, and plasma physics. In the RAPP Center, scientists conduct frontier research with the aim to significantly contribute to answering four fundamental physics questions that interlink the three subdisciplines of physics:

• What is the origin of cosmic rays?
• What is the nature of neutrinos and dark matter?
• How does the interaction of cosmic rays influence the interstellar medium – from molecular clouds to protoplanetary disks?
• How are magnetic fields generated and maintained in the Universe?

By following this unique synergistic approach, the RAPP Center combines knowledge on basic plasma and particle physics with astrophysical processes in order to understand signatures of interacting matter in the Universe. This joint approach necessitates a regular exchange about new works and results, as exemplified in the large number of topically relevant talks in the Center's seminars.