Single and Multiple Coulomb Strings in Heavy Ion Storage Rings

We interpret the results of two types of experiments at systems with low numbers of highly charged ions at very low momentum spread in the ESR and SIS heavy ion rings at GSI, namely the jump of the momentum spread in the machine experiments of Steck et al. and the anomalous frequency shifts of the precision mass measurements of Radon et al. In both cases we conclude from our calculations that the particles arrange in diluted strings in such a way that they cannot pass each other any more. Both effects are reproduced by our models.