  The Future Circular Collider (FCC) study aims at designing different options
of a post-LHC collider. The high luminosity electron-positron collider FCC-ee
based on the crab waist concept is considered as an intermediate step on the
way towards FCC-hh, a 100 TeV hadron collider using the same tunnel of about
100 km. Due to a high intensity of circulating beams the impact of collective
effects on FCC-ee performance has to be carefully analyzed. In this paper we
evaluate beam coupling impedance of the FCC-ee vacuum chamber, estimate
thresholds and rise times of eventual single- and multibunch beam instabilities
and discuss possible measures to mitigate them.
