Transverse modes and instabilities of a bunched beam with space charge and resistive wall impedance

Abstract

Transverse instability of a bunched beam is investigated with synchrotron oscillations, space charge tune shift, and resistive wall wakefield taken into account. A boxcar model is used for a general analysis, and truncated Gaussian distribution is invoked for details. The beam spectrum, instability growth rate, and effects of chromaticity are studied in a wide range of parameters, both with head-tail and collective bunch interactions included. Influence of internal bunch oscillations on the collective instabilities is investigated thoroughly. Landau damping caused by the space charge tune spread is discussed, and the instability thresholds of different modes of truncated Gaussian bunch are estimated. © 2012 American Physical Society.