Studies and Mitigation of Collective Effects in FCC-ee

In order to achieve a high luminosity in the future electron-positron circular collider (FCC-ee), very intense multi-bunch colliding beams should have nanometer scale transverse beam sizes at the collision points. For this purpose the emittances of the colliding beams are chosen to be very small, comparable to those of the modern synchrotron light sources, while the stored beam currents should be close to the best values achieved in the last generation of particle factories. In order to preserve beam quality and to avoid collider performance degradation, a careful study of the collective effects and techniques for their mitigation is required. The current status of these studies is discussed in the paper.