Varying chromaticity: A damping mechanism for the transverse head-tail instability

Varying chromaticity: A damping mechanism for the transverse head-tail instability

A detailed analytical and numerical study of the suppression of the transverse head-tail instability by modulating the chromaticity over a synchrotron period is presented. We find that a threshold can be developed, and it can be increased to a value larger than the strong head-tail instability threshold. The stability criterion derived agrees very well with the simulations. The underlying physi...

Damping of the Transverse Head-Tail Instability by Periodic Modulation of the Chromaticity

An analytical and numerical study of the suppression of the transverse head-tail instability by modulating the chromaticity over a synchrotron period is presented. We find that a threshold can be developed, and it can be increased to a value larger than the strong head-tail instability threshold. The stability criterion derived agrees very well with the simulations. The underlying physical mech...

Theory of Head - Tail Chromaticity Sharingr

Chromaticity compensation (Q 0 x Q 0 y 0) is required to avoid the \head-tail" eeect in all high-energy accelerators. A potential advantage of the \MM obius" scheme, or any other strongly coupled lattice, is that, because of cooperation between damping in the two planes, a less-restrictive condition, Q 0 x ?Q 0 y , should be satisfactory. This \chromaticity sharing" concept has been tested at C...

The Measurement of Chromaticity by Head-tail Phase Shift Analysis

Destabilising Effect of Linear Coupling in the Hera Proton Ring

Since the first start-up of HERA in 1992, a transverse coherent instability has appeared from time to time at the beginning of the acceleration ramp. In this process, the emittance is blown up and the beam is partially or completely lost. Although the instability was found to be of the head-tail type, and the chromaticity and linear coupling between the transverse planes was recognized as essen...