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Tolerances to driver-witness misalignment in a quasilinear plasma wakefield accelerator

T. C. Wilson

J. Farmer

K. Lotov

A. Pukhov

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Phys. Rev. Accel. Beams 29, 103602 – Published 20 October, 2026

DOI: https://doi.org/10.1103/47mg-t29q

Abstract

Plasma-based accelerators offer high accelerating gradients and scalability through staging or long plasma sources, which makes them good candidates for future accelerator and collider concepts. Proton-driven accelerators in particular have the potential to bring particles to high energy in a single stage. In the quasilinear regime, where the plasma wake is only partially evacuated, a witness bunch of electrons drives a cavitated wake that acts to preserve the emittance of the portion of the witness inside this self-blowout. In the case of a misalignment between the driver and witness, this behavior can persist, but its effectiveness is reduced. In this paper, we study transverse witness dynamics in this regime and develop an analytical model to describe the witness motion. We show that the degree of emittance preservation can be predicted by estimating the beam density after phase-mixing. Particle-in-cell simulations using the AWAKE Run 2c baseline parameters show excellent agreement with the predictive model developed. This work allows alignment constraints to be set both for the AWAKE experiment and other wakefield acceleration schemes operating in the quasilinear regime.

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References (30)

  1. M. Litos et al., 9 GeV energy gain in a beam-driven plasma wakefield accelerator, Plasma Phys. Controlled Fusion 58, 034017 (2016).
  2. C. Zhang et al., Plasma-wakefield accelerator simultaneously boosts electron beam energy and brightness, Nat. Commun. 16, 10719 (2025).
  3. B. Foster, R. D’Arcy, and C. A. Lindstrøm, A hybrid, asymmetric, linear higgs factory based on plasma-wakefield and radio-frequency acceleration, New J. Phys. 25, 093037 (2023).
  4. J. Farmer, A. Caldwell, and A. Pukhov, Preliminary investigation of a higgs factory based on proton-driven plasma wakefield acceleration, New J. Phys. 26, 113011 (2024).
  5. A. Caldwell et al., Proton-driven plasma wakefield acceleration for future HEP colliders, arXiv:2503.21669.
  6. T. Tajima and J. M. Dawson, Laser electron accelerator, Phys. Rev. Lett. 43, 267 (1979).
  7. P. Chen, J. M. Dawson, R. W. Huff, and T. Katsouleas, Acceleration of electrons by the interaction of a bunched electron beam with a plasma, Phys. Rev. Lett. 54, 693 (1985).
  8. C. A. Lindstrøm, Staging of plasma-wakefield accelerators, Phys. Rev. Accel. Beams 24, 014801 (2021).
  9. A. Caldwell, K. Lotov, A. Pukhov, and F. Simon, Proton-driven plasma-wakefield acceleration, Nat. Phys. 5, 363 (2009).
  10. E. Gschwendtner et al., AWAKE, the advanced proton driven plasma wakefield acceleration experiment at CERN, NIM-A 829, 76 (2016).
  11. E. Gschwendtner et al., The AWAKE run 2 programme and beyond, Symmetry 14, 1680 (2022).
  12. N. Kumar, A. Pukhov, and K. Lotov, Self-modulation instability of a long proton bunch in plasmas, Phys. Rev. Lett. 104, 255003 (2010).
  13. AWAKE Collaboration, Experimental observation of proton bunch modulation in a plasma, at varying plasma densities, Phys. Rev. Lett. 122, 054802 (2019).
  14. K. V. Lotov, A. P. Sosedkin, A. V. Petrenko, L. D. Amorim, J. Vieira, R. A. Fonseca, L. O. Silva, E. Gschwendtner, and P. Muggli, Electron trapping and acceleration by the plasma wakefield of a self-modulating proton beam, Phys. Plasmas 21, 123116 (2014).
  15. F. Willeke, Study of acceleration and compression of proton bunches for proton-driven plasma acceleration, in First PEEP Workshop (2024), https://indico.cern.ch/event/1458898.
  16. J. Flowerdew et al., Quadrupole pumping for bunch shortening in the proton synchrotron and super proton synchrotron at CERN, in Proc. IPAC‘25 (JACoW Publishing, Geneva, Switzerland, 2025), p. 2302.
  17. J. B. Rosenzweig, B. Breizman, T. Katsouleas, and J. J. Su, Acceleration and focusing of electrons in two-dimensional nonlinear plasma wake fields, Phys. Rev. A 44, R6189(R) (1991).
  18. V. K. B. Olsen, E. Adli, and P. Muggli, Emittance preservation of an electron beam in a loaded quasilinear plasma wakefield, Phys. Rev. Accel. Beams 21, 011301 (2018).
  19. E. Adli et al., Transverse tolerances in the plasma-wakefield acceleration blowout regime, in Proc. IPAC‘25 (JACoW Publishing, Geneva, Switzerland, 2025), p. 1434.
  20. A. Pukhov, Particle-in-cell codes for plasma-based particle acceleration, CERN Yellow Rep. 1, 181 (2016).
  21. S. Diederichs, C. Benedetti, A. Huebl, R. Lehe, A. Myers, A. Sinn, J.-L. Vay, W. Zhang, and M. Thévenet, HiPACE++: A portable, 3d quasi-static particle-in-cell code, Comput. Phys. Commun. 278, 108421 (2022).
  22. J. P. Farmer et al., Electron witness constraints for awake, in Proc. IPAC‘21 (JACoW Publishing, Geneva, Switzerland, 2021), p. 1753.
  23. T. Mehrling, J. Grebenyuk, F. S. Tsung, K. Floettmann, and J. Osterhoff, Transverse emittance growth in staged laser-wakefield acceleration, Phys. Rev. Accel. Beams 15, 111303 (2012).
  24. T. Katsouleas et al., Beam loading in plasma accelerators, Part. Accel. 22, 81 (1987).
  25. R. Keinigs and M. E. Jones, Two-dimensional dynamics of the plasma wakefield accelerators, Phys. Fluids 30, 252 (1987).
  26. K. V. Lotov, Blowout regimes of plasma wakefield acceleration, Phys. Rev. E 69, 046405 (2004).
  27. J. P. Farmer, L. Liang, R. Ramjiawan, F. M. Velotti, M. Weidl, E. Gschwendtner, and P. Muggli, Injection tolerances and self-matching in a quasilinear wakefield accelerator. EDMS document 2711602/1.0, CERN, 2022.
  28. S. Romeo, M. Ferrario, and A. R. Rossi, Beam loading assisted matching scheme for high quality plasma acceleration in linear regime, Phys. Rev. Accel. Beams 23, 071301 (2020).
  29. R. Ramjiawan, S. Döbert, J. Farmer, E. Gschwendtner, F. M. Velotti, L. Verra, G. Z. Della Porta, V. Bencini, and P. N. Burrows, Design and operation of transfer lines for plasma wakefield accelerators using numerical optimizers, Phys. Rev. Accel. Beams 25, 101602 (2022).
  30. Gauss Centre for Supercomputing, https://www.gauss-centre.eu.

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Phys. Rev. Accel. Beams 29, 103602– Published 20 October, 2026
  • Received 27 February 2026
  • Accepted 29 September 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.

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