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Head-tail instability at Tevatron

Tevatron performance suffers from a coherent transverse instability. Experimental and theoretical studies allow identifying the instability as a weak head-tail, driven by the short-range wake fields in presence of the space charge. Growth rates and coherent tune shifts are measured at injection of single high-intensity proton bunch using a fast strip-line pickup. Landau damping through the octupole-generated betatron tune spread for all unstable head-tail modes has been demonstrated.