HESR at FAIR

The High Energy Storage Ring (HESR) was originally designed as experimental storage ring for antiproton physics with the PANDA detector. It is designed for injection and acceleration of up to 1011 antiprotons in the momentum range between 1.5 GeV/c and 15 GeV/c. Due to the modularized start version of FAIR the injection had to be modified to allow the accumulation of up to 1010 antiprotons. This restricts the modes of operation for PANDA to the high resolution mode only. In addition further experimental groups, SPARC and NUSTAR, investigated the possibilities of higher energy heavy ion and atomic physics experiments. The optics of the High Energy Storage Ring, the modes of operation for different experiments and different ion species will be discussed.