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  • Open Access

Global Kinetic Simulations of Monster Shocks and Their Emission

Dominic Bernardi*, Yajie Yuan†, and Alexander Y. Chen‡

  • *Contact author: bdominic@wustl.edu
  • †Contact author: yajiey@wustl.edu
  • ‡Contact author: cyuran@wustl.edu
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Phys. Rev. Lett. 135, 265201 – Published 22 December, 2025

DOI: https://doi.org/10.1103/y9p7-1zms

Abstract

Fast magnetosonic waves are one of the two low-frequency plasma modes that can exist in a neutron star magnetosphere. It was recently realized that these waves may become nonlinear within the magnetosphere and steepen into some of the strongest shocks in the universe. These shocks, when in the appropriate parameter regime, may emit GHz radiation in the form of precursor waves. We present the first global particle-in-cell simulations of the nonlinear steepening of fast magnetosonic waves in a dipolar magnetosphere, and quantitatively demonstrate the strong plasma acceleration in the upstream of these shocks. In these simulations, we observe the production of precursor waves in a finite angular range. Using analytic scaling relations, we predict the expected frequency, power, and duration of this emission. Within a reasonable range of progenitor wave parameters, these precursor waves can reproduce many aspects of FRB observations.

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References (49)

  1. V. M. Kaspi and A. M. Beloborodov, Magnetars, Annu. Rev. Astron. Astrophys. 55, 261 (2017).
  2. S. Mereghetti, J. A. Pons, and A. Melatos, Magnetars: Properties, origin and evolution, Space Sci. Rev. 191, 315 (2015).
  3. C. Thompson and R. C. Duncan, The soft gamma repeaters as very strongly magnetized neutron stars. II. Quiescent neutrino, x-ray, and Alfven wave emission, Astrophys. J. 473, 322 (1996).
  4. B. C. Andersen et al. (CHIME/FRB Collaboration), A bright millisecond-duration radio burst from a Galactic magnetar, Nature (London) 587, 54 (2020).
  5. C. D. Bochenek, V. Ravi, K. V. Belov, G. Hallinan, J. Kocz, S. R. Kulkarni, and D. L. McKenna, A fast radio burst associated with a Galactic magnetar, Nature (London) 587, 59 (2020).
  6. O. Blaes, R. Blandford, P. Goldreich, and P. Madau, Neutron starquake models for gamma-ray bursts, Astrophys. J. 343, 839 (1989).
  7. A. Bransgrove, A. M. Beloborodov, and Y. Levin, A quake quenching the vela pulsar, Astrophys. J. 897, 173 (2020).
  8. A. M. Beloborodov, Monster radiative shocks in the perturbed magnetospheres of neutron stars, Astrophys. J. 959, 34 (2023).
  9. Y. Qu and A. Bransgrove, Three-dimensional numerical simulations of magnetar crust quakes, arXiv:2508.12567.
  10. L. Burnaz, E. R. Most, and A. Bransgrove, Crustal quakes spark magnetospheric blasts: Imprints of realistic magnetar crust oscillations on the fast radio burst signal, arXiv:2508.18033.
  11. Y. Yuan, Y. Levin, A. Bransgrove, and A. Philippov, Alfvén wave mode conversion in pulsar magnetospheres, Astrophys. J. 908, 176 (2021).
  12. J. F. Mahlmann, M. Á. Aloy, and X. Li, Force-free wave interaction in magnetar magnetospheres: Computational modeling in axisymmetry, Astrophys. J. 972, 139 (2024).
  13. D. Bernardi, Y. Yuan, and A. Y. Chen, Alfvén wave conversion to low frequency fast magnetosonic waves in magnetar magnetospheres, Astrophys. J. 980, 222 (2025).
  14. A. Y. Chen, Y. Yuan, and D. Bernardi, Alfvén wave mode conversion in neutron star magnetospheres: A semianalytic approach, Astrophys. J. 987, 42 (2025).
  15. E. R. Most, A. M. Beloborodov, and B. Ripperda, Monster shocks, gamma-ray bursts, and black hole quasi-normal modes from neutron-star collapse, Astrophys. J. Lett. 974, L12 (2024).
  16. Y. Kim, E. R. Most, A. M. Beloborodov, and B. Ripperda, Black hole pulsars and monster shocks as outcomes of black hole–neutron star mergers, Astrophys. J. Lett. 982, L54 (2025).
  17. Y. E. Lyubarsky, Fast magnetosonic waves in pulsar winds, Mon. Not. R. Astron. Soc. 339, 765 (2003).
  18. A. Y. Chen, Y. Yuan, X. Li, and J. F. Mahlmann, Propagation of a strong fast magnetosonic wave in the magnetosphere of a neutron star, arXiv:2210.13506.
  19. A. Vanthieghem and A. Levinson, Fast radio bursts as precursor radio emission from monster shocks, Phys. Rev. Lett. 134, 035201 (2025).
  20. A. Y. Chen and A. M. Beloborodov, Electrodynamics of axisymmetric pulsar magnetosphere with electron-positron discharge: A numerical experiment, Astrophys. J. Lett. 795, L22 (2014).
  21. A. A. Philippov and A. Spitkovsky, Ab-initio pulsar magnetosphere: Particle acceleration in oblique rotators and high-energy emission modeling, Astrophys. J. 855, 94 (2018).
  22. B. Cerutti and G. Giacinti, A global model of particle acceleration at pulsar wind termination shocks, Astron. Astrophys. 642, A123 (2020).
  23. A. G. Sullivan, J. Cortés, and L. Sironi, Polarized emission of intrabinary shocks in spider pulsars from global 3D kinetic simulations, Astrophys. J. 991, 98 (2025).
  24. https://github.com/fizban007/Aperture4.
  25. See Supplemental Material at http://link.aps.org/supplemental/10.1103/y9p7-1zms for additional discussion which includes Refs. [26–35].
  26. J. L. Vay, Simulation of beams or plasmas crossing at relativistic velocity, Phys. Plasmas 15, 056701 (2008).
  27. T. Z. Esirkepov, Exact charge conservation scheme for particle-in-cell simulation with an arbitrary form-factor, Comput. Phys. Commun. 135, 144 (2001).
  28. A. Y. Chen, M. Luepker, and Y. Yuan, Introducing aperture: A GPU-based general relativistic particle-in-cell simulation framework, arXiv:2503.04558.
  29. B. Cerutti, A. Philippov, K. Parfrey, and A. Spitkovsky, Particle acceleration in axisymmetric pulsar current sheets, Mon. Not. R. Astron. Soc. 448, 606 (2015).
  30. A. Y. Chen, Particle-in-cell simulations and their applications to magnetospheres of neutron stars, Ph.D. thesis, Columbia University, 2017.
  31. A. Y. Chen, F. Cruz, and A. Spitkovsky, Filling the magnetospheres of weak pulsars, Astrophys. J. 889, 69 (2020).
  32. A. Y. Chen and A. M. Beloborodov, Particle-in-cell simulations of the twisted magnetospheres of magnetars. I, Astrophys. J. 844, 133 (2017).
  33. J. D. Jackson, Classical electrodynamics, 3rd ed. (Wiley, New York, NY, 1999).
  34. Y. Yuan, A. M. Beloborodov, A. Y. Chen, Y. Levin, E. R. Most, and A. A. Philippov, Magnetar bursts due to Alfvén wave nonlinear breakout, Astrophys. J. 933, 174 (2022).
  35. Y. Zhang, Y. Yang, and L. Ji, Radiation reaction effects on coherent emission in relativistic magnetized shocks, arXiv:2502.14550.

  36. Click here (https://youtu.be/LyQCaSag0Zc) for a YouTube video of these shocks.

  37. D. Alsop and J. Arons, Relativistic magnetosonic solitons with reflected particles in electron-positron plasmas, Phys. Fluids 31, 839 (1988).
  38. A. Vanthieghem and A. Levinson, Relativistically magnetized collisionless shocks in pair plasma: Solitons, chaos, and thermalization, Phys. Rev. E 111, 045209 (2025).
  39. Y. A. Gallant, M. Hoshino, A. B. Langdon, J. Arons, and C. E. Max, Relativistic, perpendicular shocks in electron-positron plasmas, Astrophys. J. 391, 73 (1992).
  40. I. Plotnikov and L. Sironi, The synchrotron maser emission from relativistic shocks in fast radio bursts: 1D PIC simulations of cold pair plasmas, Mon. Not. R. Astron. Soc. 485, 3816 (2019).
  41. L. Sironi and A. Spitkovsky, Particle acceleration in relativistic magnetized collisionless pair shocks: Dependence of shock acceleration on magnetic obliquity, Astrophys. J. 698, 1523 (2009).
  42. W. A. Majid, A. B. Pearlman, T. A. Prince, R. S. Wharton, C. J. Naudet, K. Bansal, L. Connor, M. Bhardwaj, and S. P. Tendulkar, A bright fast radio burst from FRB 20200120E with sub-100 nanosecond structure, Astrophys. J. Lett. 919, L6 (2021).
  43. P. Goldreich and W. H. Julian, Pulsar electrodynamics, Astrophys. J. 157, 869 (1969).
  44. S. Mereghetti et al., INTEGRAL discovery of a burst with associated radio emission from the magnetar SGR 1935+2154, Astrophys. J. Lett. 898, L29 (2020).
  45. A. Ridnaia, D. Svinkin, D. Frederiks, A. Bykov, S. Popov, R. Aptekar, S. Golenetskii, A. Lysenko, A. Tsvetkova, M. Ulanov, and T. L. Cline, A peculiar hard x-ray counterpart of a Galactic fast radio burst, Nat. Astron. 5, 372 (2021).
  46. C. K. Li et al., HXMT identification of a non-thermal x-ray burst from SGR J1935+2154 and with FRB 200428, Nat. Astron. 5, 378 (2021).
  47. A.-N. Babul and L. Sironi, The synchrotron maser emission from relativistic magnetized shocks: dependence on the pre-shock temperature, Mon. Not. R. Astron. Soc. 499, 2884 (2020).
  48. S. D. Ryder et al., A luminous fast radio burst that probes the Universe at redshift 1, Science 382, 294 (2023).
  49. C. Thompson and R. C. Duncan, The soft gamma repeaters as very strongly magnetized neutron stars—I. Radiative mechanism for outbursts, Mon. Not. R. Astron. Soc. 275, 255 (1995).

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Phys. Rev. Lett. 135, 265201– Published 22 December, 2025
  • Received 4 June 2025
  • Accepted 1 December 2025
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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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