Head-tail stability and linear coupling in the Tevatron

During collider studies it was observed that with bunch intensities of >60*10/sup 9/ particles per bunch in the Tevatron, the beam would go unstable if the machine ran close to the coupling resonance. Simple head-tail stability only requires the horizontal and vertical chromaticities to be positive. Since the beam went unstable even when this condition was met, a set of experiments were performed which showed that if there is significant linear coupling the head-tail stability criterion is modified. A formalism for calculating head-tail stability is presented. The predictions of the formalism are compared to data taken with the Tevatron.<
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