Incoherent effects driven by the electron cloud

As a result of the synchrotron radiation from a positively-charged beam, an electron cloud is expected to develop in the vacuum chamber from the combined effects of the photoelectric and secondary emission processes. We provide here a first estimate of the electron-cloud effect on individual particles of the beam. We focus on the space-charge tune spread, the distortion of the beta function and the dispersion, and synchro-betatron coupling. We illustrate the effects with numerical applications to the PEP-II positron ring. We conclude that the magnitude of the effect is not negligible, although it is not large either. However, the present calculations can only be considered as a first estimate, since they do not include details of the electron cloud formation in different regions of the ring