GSI, Darmstadt
The effect of space charge on the transverse Schottky spectrum of coasting and bunched beams is studied using measurements and simulations together with analytic models. The measurements of transverse Schottky bands from heavy ion beams are performed in the SIS-18 synchrotron at GSI. In addition we analyze the noise spectrum from a particle tracking code with self-consistent space charge. Both results are compared to analytic models for coasting and for bunched beams with space charge. For coasting beams an analytic model based on the transverse dispersion relation with linear space and chromaticity reproduces the characteristic deformation of Schottky bands with increasing space charge, observed in both measurement and simulation. For bunched beams we find good agreement between the observed shifts of synchrotron satellites and a simplified model for head-tail modes with space charge. The relevance of the results for the analysis of transverse beam stability in the presence of space charge is emphasized.
