Physical Review Accelerators and Beams (Oct 2024)

Effects of space charge force on the beam-beam mode coupling instability

  • Kazuhito Ohmi,
  • Yuan Zhang

DOI
https://doi.org/10.1103/PhysRevAccelBeams.27.101001
Journal volume & issue
Vol. 27, no. 10
p. 101001

Abstract

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Recent e^{+}e^{-} colliders operate with very low emittance and high current. The space-charge tune shift is not negligible in tau-charm and B factories. The vertical space-charge tune shift is on the order of 0.02–0.1 and is comparable to the synchrotron tune and the beam-beam tune shift. The beam-beam mode coupling instability has been studied with and without vacuum environment impedance. The mode coupling is influenced by the space-charge force, which exhibits similar characteristics to the beam-beam force. The combined effect of beam-beam, space charge, and vacuum environment impedance is discussed within the framework of the mode coupling theory. Strong-strong beam-beam simulation, considering the space-charge force and the impedance, are conducted to validate the theory and to study general cases such as asymmetric colliders.