Review of collective beam instabilities in electron-positron storage rings

Abstract

The review of studies of collective beam instabilities in electron positron storage rings is pre sented. The processes of excitation and suppression of the longitudinal microwave instability, transverse mode coupling instability, longitudinal and transverse multi bunch instabilities, and instabilities induced by an interaction of a beam with ions or electron clouds are discussed. Important equations for estimation of the threshold beam currents and the rise time of instabilities, as well as the references to the major original works are given. The methods for diagnostics and suppression of instabilities are considered using specific examples.

Measurement and parametric analysis of transverse coupled bunch instabilities for electron synchrotron radiation source Indus-2

“…In the synchrotron radiation sources, transverse beam instabilities include mode-coupling instability, coupled-bunch instability, head-tail instability and coasting beam instability etc. These beam instabilities may excites under specific conditions [4,5].…”

Feedback for suppression of single-bunch transverse instability in electron-positron storage rings

“…As it was found, even without any feedback it is possible to exceed the threshold current of TMC instability by increasing the chromaticity and nonlinearity of the magnet lattice. The beam stability with chromatic and nonlinear effects was experimentally investigated at the VEPP-3, VEPP-4M [22,29,30] (Budker Institute, Novosibirsk) and Elettra (Sincrotrone Trieste) [31,32] storage rings. Similar effects were also observed at KEK Photon Factory [33].…”

“…For better understanding of the processes of beam oscillation excitation and suppression, taking into account the fast head-tail instability, chromatic head-tail effect, and oscillation decoherence caused by chromaticity and nonlinearity, numerical simulation based on multi-particle tracking turns out to be useful [22]. In the model, the bunch is represented as an ensemble of N p macroparticles, which have a Gaussian initial distribution of the amplitudes of betatron and synchrotron oscillations and a uniform distribution of the oscillation phases.…”