Speaker
Kevin Shing Bruce Li
(CERN)
Description
Beside the beam's own space charge, collective effects are typically triggered by the direct electromagnetic interaction of the beam with the external chamber and equipment, described through wake fields and beam-coupling impedances, and the interaction of the beam with electron or ion clouds generated in the vacuum chamber through vacuum or surface processes. They manifest themselves as macroscopic responses of the particle beams to intensity dependent excitations, resulting in observables such as coherent tune shifts, coherent instabilities or emittance growth.
