On Transverse mode coupling instability in VLHC

Abstract

We present the results of calculation of transverse mode coupling instability (TMCI) thresholds for Very Large Hadron Collider (VLHC). The estimates are done with use of conventional approach and more sophisticated mode dynamics analysis. We found the RF system parameters which allows to get appropriate TMCI threshold number of particles per bunch and attain high luminosity of the collider. Alternative ways to raise the threshold are briefly discussed.

Considerations on compensation of beam-beam effects in the Tevatron with electron beams

“…In Ref. [9] we discuss the possibility of adding a single thin nonlinear lens to some arbitrary nonlinear lattice in such a way that the particle motion in the modified structure would become resonance free, though nonlinear, and the beam of particles would have a zero footprint. A numerical method to construct such maps is as follows: let us choose the tune equal to a resonant one, e.g., the 20th order resonance.…”

Electron lenses: historical overview and outlook

“…Besides discussions on the practical issues of the Tevatron beam-beam compensation and electron lens technology, the Workshop established very fruitful collaborative ties which have greatly expanded since. Several interesting new concepts were presented there, too, including plasma-suppression of beam-beam interaction, most practical at the interaction point of muon colliders [42], and the possibility of improved (more stable) beam dynamics in accelerator focusing lattices with a single nonlinear electron lens [43].…”

Evaluation of "round colliding beams" for Tevatron

“…Moreover, the beam-beam parameter for the round beams x;y = Nr0 4 " ; does not depend on s because the emittance " = 2 = is independent of the longitudinal coordinate. This leads to suppression of synchrobetatron resonances (one can find more detailed discussion of these questions in [2]). …”