Increasing the transverse mode coupling instability threshold by RF quadrupole

Abstract

Transverse mode coupling instability is one of the major limitations of a single bunch current in storage rings. Until now it has appeared in large electron-positron machines, while its presence in proton colliders has not been observed. This paper describes a theoretical analysis of the effect of longitudinal variation of the betatron tune on the transverse mode coupling instability. This variation can be introduced by an RF quadrupole. In the result, the instability threshold could be significantly increased when a modulation of the betatron frequency is comparable with the synchrotron tune. © 1998 The American Physical Society.