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  • Open Access

Circular-mode optics for high-intensity beams and high-luminosity colliders

Onur Gilanliogullari*,†

Brahim Mustapha

Pavel Snopok

  • *Contact author: onur.gilanliogullari@physics.uu.se
  • †Present address: Department of Physics and Astronomy, FREIA Division, Uppsala University, Uppsala, Sweden.
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Phys. Rev. Accel. Beams 29, 103202 – Published 28 October, 2026

DOI: https://doi.org/10.1103/1drd-x8kp

Abstract

We study circular-mode optics as a framework for transporting and accelerating intrinsically flat beams while maintaining a round transverse projection in physical space. Motivated by the strong degradation of flat beams under low-energy space-charge forces, we develop a coupled-optics description of circular modes, analyze their formation and preservation, and derive lattice design conditions for conserving canonical angular momentum and coupling phase. These conditions motivate rotationally invariant transport and ring cells based on solenoids, symmetric alternating-gradient structures, and indexed dipoles. We further derive space-charge tune-shift and tune-spread expressions for circular-mode beams in uncoupled and coupled lattices, showing that they preserve the leading-order space-charge behavior of round beams while retaining intrinsic eigenemittance flatness. Particle-in-cell simulations with TRACK and impactx confirm the generation, transport, and acceleration of circular-mode beams in representative lattices, including regimes with strong space charge. Circular-mode optics therefore provides a promising route toward high-intensity hadron beams and high-luminosity collider applications.

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Phys. Rev. Accel. Beams 29, 103202– Published 28 October, 2026
  • Received 27 April 2026
  • Accepted 5 October 2026
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