- Physical Review Journals
All JournalsPhysics Magazine

Physical Review Letters

Reuse & Permissions

It is not necessary to obtain permission to reuse this article or its components as it is available under the terms of the Creative Commons Attribution 4.0 International license. This license permits unrestricted use, distribution, and reproduction in any medium, provided attribution to the author(s) and the published article's title, journal citation, and DOI are maintained. Please note that some figures may have been included with permission from other third parties. It is your responsibility to obtain the proper permission from the rights holder directly for these figures.

Export citation

Export citation

Choose format for download:

Download Citation
  • Open Access

How Zonal Fields Suppress Reversed Shear Alfvén Eigenmode in Tokamak Plasmas

Ruirui Ma1,2, Pengfei Liu3, Liu Chen4,2,*, Fulvio Zonca2,5, and Zhiyong Qiu6,2

  • *Contact author: liuchen@uci.edu
PDF

Phys. Rev. Lett. 137, 045101 – Published 21 July, 2026

DOI: https://doi.org/10.1103/hh65-rgwv

Abstract

Understanding nonlinear saturation of reversed-shear Alfvén eigenmodes (RSAEs) in tokamaks is crucial for high-performance burning plasmas. Employing both nonlinear gyrokinetic simulations and theoretical analyses, we have discovered the novel result that, with energetic particle dynamics kept linear, the nonlinear suppression and eventual saturation of RSAE occur via the downward frequency chirping induced by the beat-driven zonal current. More specifically, as the mode frequency chirps downward, there is enhanced mode conversion to radially propagating electron Landau-damped kinetic Alfvén waves; resulting in enhanced convective (radiative) damping and, thereby, its suppression and saturation. Theoretical results are in good agreement with simulations both qualitatively and quantitatively. This Letter, thus, establishes a fundamental framework for zonal-current mediated saturation of Alfvén eigenmodes in burning plasmas.

View figure in article

Physics Subject Headings (PhySH)

Article Text

References (34)

  1. H. Kimura, Y. Kusama, M. Saigusa, G. J. Kramer, K. Tobita, M. Nemoto, T. Kondoh, T. Nishitani, O. D. Costa, T. Ozeki et al., Nucl. Fusion 38, 1303 (1998).
  2. S. E. Sharapov, D. Testa, B. Alper, D. N. Borba, A. Fasoli, N. C. Hawkes, R. F. Heeter, M. Mantsinen, and M. G. V. Hellermann (The EFDA-JET Work Programme Collaboration), Phys. Lett. A 289, 127 (2001).
  3. R. Nazikian, G. J. Kramer, C. Z. Cheng, N. N. Gorelenkov, H. L. Berk, and S. E. Sharapov, Phys. Rev. Lett. 91, 125003 (2003).
  4. P. Liu, X. Wei, Z. Lin, G. Brochard, G. J. Choi, W. W. Heidbrink, J. H. Nicolau, and G. R. McKee, Phys. Rev. Lett. 128, 185001 (2022).
  5. L. Chen, Z. Lin, R. White, and F. Zonca, Nucl. Fusion 41, 747 (2001).
  6. P. H. Diamond, S. I. Itoh, K. Itoh, and T. S. Hahm, Plasma Phys. Controlled Fusion 47, R35 (2005).
  7. L. Chen and F. Zonca, Phys. Rev. Lett. 109, 145002 (2012).
  8. J. Li and Y. Kishimoto, Phys. Rev. Lett. 89, 115002 (2002).
  9. A. Hasegawa and L. Chen, Phys. Rev. Lett. 35, 370 (1975).
  10. A. Hasegawa and L. Chen, Phys. Fluids 19, 1924 (1976).
  11. Y. Chen, G. Fu, C. Collins, S. Taimourzadeh, and S. Parker, Phys. Plasmas 25, 032304 (2018).
  12. T. Wang, S. Wei, S. Briguglio, G. Vlad, F. Zonca, and Z. Qiu, Plasma Sci. Technol. 26, 053001 (2024).
  13. P. Liu, X. Wei, Z. Lin, G. Brochard, G. Choi, and J. Nicolau, Rev. Mod. Plasma Phys. 7, 15 (2023).
  14. L. Chen and F. Zonca, Phys. Plasmas 20, 055402 (2013).
  15. S. Wei, T. Wang, N. Chen, and Z. Qiu, J. Plasma Phys. 87, 905870505 (2021).
  16. F. Zonca, L. Chen, S. Briguglio, G. Fogaccia, G. Vlad, and X. Wang, New J. Phys. 17, 013052 (2015).
  17. F. Zonca, L. Chen, M. V. Falessi, and Z. Qiu, J. Phys. Conf. Ser. 1785, 012005 (2021).
  18. M. V. Falessi, L. Chen, Z. Qiu, and F. Zonca, New J. Phys. 25, 123035 (2023).
  19. L. Chen, P. Liu, R. Ma, Z. Lin, Z. Qiu, W. Wang, and F. Zonca, Nucl. Fusion 65, 016018 (2025).
  20. Z. Lin, T. Hahm, W. Lee, W. Tang, and R. White, Science 281, 3 (1998).
  21. C. S. Collins, W. W. Heidbrink, M. E. Austin, G. J. Kramer, D. C. Pac e, C. C. Petty, L. Stagner, M. A. Van Zeeland, R. B. White, and Y. B. Zhu (DIII-D Team Collaboration), Phys. Rev. Lett. 116, 095001 (2016).
  22. P. Liu, X. Wei, Z. Lin, W. Heidbrink, G. Brochard, G. Choi, J. Nicolau, and W. Zhang, Nucl. Fusion 64, 076007 (2024).
  23. Z. Lin and L. Chen, Phys. Plasmas 8, 1447 (2001).
  24. J. Bao, W. Zhang, D. Li, Z. Lin, G. G. Dong, C. Liu, H. Xie, G. Meng, J. Cheng, C. Dong et al., Nucl. Fusion 63, 076021 (2023).
  25. E. A. Frieman and L. Chen, Phys. Fluids B 25, 502 (1982).
  26. L. Chen and F. Zonca, Rev. Mod. Phys. 88, 015008 (2016).
  27. F. Zonca, S. Briguglio, L. Chen, S. Dettrick, G. Fogaccia, D. Testa, and G. Vlad, Phys. Plasmas 9, 4939 (2002).
  28. N. Winsor, J. Johnson, and J. Dawson, Phys. Fluids 11, 2448 (1968).
  29. A. D. Turnbull, E. J. Strait, W. W. Heidbrink, M. S. Chu, H. H. Duong, J. W. Greene, L. L. Lao, T. S. Taylor, and S. J. Thompson, Phys. Fluids B 5, 2546 (1993).
  30. F. Zonca, L. Chen, and R. A. Santoro, Plasma Phys. Controlled Fusion 38, 2011 (1996).
  31. L. Yu, G.-Y. Fu, and Z.-M. Sheng, Phys. Plasmas 16, 072505 (2009).
  32. H. L. Berk, R. Mett, and D. Lindberg, Phys. Fluids B 5, 3969 (1993).
  33. W. Deng, Z. Lin, I. Holod, Z. Wang, Y. Xiao, and H. Zhang, Nucl. Fusion 52, 043006 (2012).
  34. W. W. Heidbrink, C. S. Collins, M. Podestà, G. J. Kramer, D. C. Pace, C. C. Petty, L. Stagner, M. A. Van Zeeland, R. B. White, and Y. B. Zhu, Phys. Plasmas 24, 056109 (2017).

Outline

Information

Phys. Rev. Lett. 137, 045101– Published 21 July, 2026
  • Received 20 November 2025
  • Accepted 26 June 2026
Crossmark - Check for updates button
Creative Commons Logo

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.

Published by the American Physical Society

Sign In to Your Journals Account

Filter

Filter

Article Lookup

Enter a citation