Low Energy Storage Rings: Opening Routes for Beyond State-of-the-art Research

Electrostatic storage rings have proven to be invaluable tools for atomic and molecular physics at the ultra-low energy range from 1 to 100 keV/A. Due to the mass independence of the electrostatic rigidity these machines are able to store a wide range of different particles, from light ions to heavy singly charged bio-molecules. Their beam dynamics is, however, fundamentally different to magnetic storage rings and therefore needs to be investigated in detail to optimize storage ring performance and experimental output. This paper first gives an overview of existing electrostatic storage rings and their experimental programs. Second, future machines in Heidelberg, Stockholm and the Facility for Antiproton and Ion Research (FAIR) are described and the main challenges are summarized. Finally, the focus is set on a flexible storage ring facility presently being built up at the King Abdulaziz Center for Science and Technology (KACST) in Riyadh, Saudi Arabia, that addresses a broad user community and will allow for a next-generation experimental program in the low energy regime.