Multiple regions of shock-accelerated particles during a solar coronal mass ejection



The Sun is an active star that can launch large eruptions of magnetized plasma into the heliosphere, known as coronal mass ejections (CMEs). These can drive shocks that accelerate particles to high energies, often resulting in radio emission at low frequencies (<200 MHz). So far, the relationship between the expansion of CMEs, shocks and particle acceleration is not well understood, partly due to the lack of radio imaging at low frequencies during the onset of shock-producing CMEs. Here, we report multi-instrument radio, white-light and ultraviolet imaging of the second largest flare in solar cycle 24 (2008–present) and its associated fast CME (3,038 ± 288 km s−1). We identify the location of a multitude of radio shock signatures, called herringbones, and find evidence for shock-accelerated electron beams at multiple locations along the expanding CME. These observations support theories of non-uniform, rippled shock fronts driven by an expanding CME in the solar corona.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: The solar flare, CME and associated radio emission observed on 10 September 2017.
Fig. 2: Sequence of LOFAR tied-array filled contours showing the location of the radio shock signatures observed in Fig. 1d.
Fig. 3
Fig. 4: The location in 2D and 3D of an individual herringbone.
Fig. 5: The movement of radio sources through time and the Alfvén speed environment.
Fig. 6: The CME and Alfvén speeds.

Data availability

The LOFAR dataset used was obtained under the project code DDT8_005 and it is available in the LOFAR Long Term Archive (LTA; The I-LOFAR data can be obtained from or on request to The AIA and LASCO datasets are both available from the Virtual Solar Observatory project ( The SUVI data were made available by NOAA’s National Centers for Environmental Information SUVI team as a community service to the solar physics community studying the September 2017 flaring events ( These datatsets are also available from the authors upon request.

Change history

  • 24 April 2019

    In the version of this Article originally published, the following ‘Journal peer review information’ was missing: “Nature Astronomy thanks Iver Cairns, Silja Pohjolainen, Zhongwei Yang and the other anonymous reviewer(s) for their contribution to the peer review of this work.” This statement has now been added.


  1. 1.

    Krivolutsky, A. A. & Repnev, A. I. Impact of space energetic particles on the Earth’s atmosphere (a review). Geomagn. Aeronomy 52, 685 (2012).

    ADS  Article  Google Scholar 

  2. 2.

    Odert, P., Leitzinger, M., Hanslmeier, A. & Lammer, H. Stellar coronal mass ejections – I. Estimating occurrence frequencies and mass-loss rates. Mon. Not. R. Astron. Soc. 472, 876–890 (2017).

    ADS  Article  Google Scholar 

  3. 3.

    Airapetian, V. S. et al. How hospitable are space weather affected habitable zones? The role of ion escape. Astrophys. J. Lett. 836, L3 (2017).

    ADS  Article  Google Scholar 

  4. 4.

    Yurchyshyn, V., Yashiro, S., Abramenko, V., Wang, H. & Gopalswamy, N. Statistical distributions of speeds of coronal mass ejections. Astrophys. J. 619, 599 (2005).

    ADS  Article  Google Scholar 

  5. 5.

    Ruzmaikin, A., Feynman, J. & Stoev, S. A. Distribution and clustering of fast coronal mass ejections. J. Geophys. Res. 116, A04220 (2011).

    ADS  Article  Google Scholar 

  6. 6.

    Klassen, A. et al. Solar energetic electron events and coronal shocks. Astron. Astrophys. 385, 1078–1088 (2002).

    ADS  Article  Google Scholar 

  7. 7.

    Mann, G. et al. Catalogue of solar type II radio bursts observed from September 1990 to December 1993 and their statistical analysis. Astron. Astrophys. Supp. 119, 489 (1996).

    ADS  Article  Google Scholar 

  8. 8.

    Nelson, G. J. & Melrose, D. B. in Solar Radiophysics: Studies of Emission from the Sun at Metre Wavelengths (eds McLean, D. J. & Labrum, N. R.) 333–359 (Cambridge Univ. Press, Cambridge and New York, 1985).

  9. 9.

    Wild, J. P. Observations of the spectrum of high-intensity solar radiation at metre wavelengths. II. Outbursts. Aust. J. Sci. Res. Ser. A. 3, 399 (1950).

    ADS  Google Scholar 

  10. 10.

    Stewart, R. T., Howard, R. A., Hansen, F., Gergely, T. & Kundu, M. Observations of coronal disturbances from 1 to 9 Rsun. II: Second event of 1973, January 11. Sol. Phys. 36, 219–231 (1974).

    ADS  Article  Google Scholar 

  11. 11.

    Smerd, S. F. Radio evidence for the propagation of magnetohydrodynamic waves along curved paths in the solar corona. Proc. Astron. Soc. Aust. 1, 305–308 (1970).

    ADS  Article  Google Scholar 

  12. 12.

    Schmidt, J. M., Cairns, I. H. & Hillan, D. S. Prediction of type II solar radio bursts by three-dimensional MHD coronal mass ejection and kinetic radio emission simulations. Astrophys. J. Lett. 773, L30 (2013).

    ADS  Article  Google Scholar 

  13. 13.

    Zucca, P. et al. Shock location and CME 3-D reconstruction of a solar type II radio burst with LOFAR. Astron. Astrophys. 615, A89 (2018).

    Article  Google Scholar 

  14. 14.

    Mann, G. & Klassen, A. Electron beams generated by shock waves in the solar corona. Astron. Astrophys. 441, 319–326 (2005).

    ADS  Article  Google Scholar 

  15. 15.

    Cairns, I. H. & Robinson, R. D. Herringbone bursts associated with type II solar radio emission. Sol. Phys. 111, 365 (1987).

    ADS  Article  Google Scholar 

  16. 16.

    Cane, H. V. & White, S. M. On the source conditions for herringbone structure in type II solar radio bursts. Sol. Phys. 120, 137 (1989).

    ADS  Article  Google Scholar 

  17. 17.

    Kundu, M. R. Solar Radio Astronomy (Interscience, New York, 1965).

  18. 18.

    Holman, G. D. & Pesses, M. E. Solar type II radio emission and the shock drift acceleration of electrons. Astrophys. J. 267, 837–843 (1983).

    ADS  Article  Google Scholar 

  19. 19.

    Zlobec, P., Messerotti, M., Karlicky, M. & Urbarz, H. Fine structures in time profiles of type II bursts at frequencies above 200 MHz. Sol. Phys. 144, 373 (1993).

    ADS  Article  Google Scholar 

  20. 20.

    Vandas, M. & Karlický, M. Electron acceleration in a wavy shock front. Astron. Astrophys. 531, A55 (2011).

    ADS  Article  Google Scholar 

  21. 21.

    Carley, E. P., Reid, H., Vilmer, N. & Gallagher, P. T. Low frequency radio observations of bi-directional electron beams in the solar corona. Astron. Astrophys. 581, A100 (2015).

    ADS  Article  Google Scholar 

  22. 22.

    Schmidt, J. M. & Cairns, I. H. Type II radio bursts: 2. Application of the new analytic formalism. J. Geophys. Res. 117, A16 (2012).

    Google Scholar 

  23. 23.

    Carley, E. P. et al. Quasiperiodic acceleration of electrons by a plasmoid-driven shock in the solar atmosphere. Nat. Phys. 9, 811 (2013).

    Article  Google Scholar 

  24. 24.

    Aurass, H., Vršnak, B. & Mann, G. Shock-excited radio burst from reconnection outflow jet? Astron. Astrophys. 384, 273 (2002).

    ADS  Article  Google Scholar 

  25. 25.

    Mann, G., Warmuth, A. & Aurass, H. Generation of highly energetic electrons at reconnection outflow shocks during solar flares. Astron. Astrophys. 494, 669–675 (2009).

    ADS  Article  Google Scholar 

  26. 26.

    Lemen, J. R. et al. The atmospheric imaging assembly (AIA) on the solar dynamics observatory (SDO). Sol. Phys. 275, 17–40 (2012).

    ADS  Article  Google Scholar 

  27. 27.

    Seaton, D. B. & Darnel, J. M. Observations of an eruptive solar flare in the extended EUV solar corona. Astrophys. J. Lett. 852, L9 (2018).

    ADS  Article  Google Scholar 

  28. 28.

    Brueckner, G. E. et al. The large angle spectroscopic coronagraph (LASCO). Sol. Phys. 162, 357–402 (1995).

    ADS  Article  Google Scholar 

  29. 29.

    Vourlidas, A., Lynch, B. J., Howard, R. A. & Li, Y. How many CMEs have flux ropes? Deciphering the signatures of shocks, flux ropes, and prominences in coronagraph observations of CMEs. Sol. Phys. 284, 179–201 (2013).

    ADS  Google Scholar 

  30. 30.

    van Haarlem et al. LOFAR: the LOw-frequency ARray. Astron. Astrophys. 556, A2 (2013).

    Article  Google Scholar 

  31. 31.

    Morosan, D. E. et al. LOFAR tied-array imaging of type III solar radio bursts. Astron. Astrophys. 568, A67 (2014).

    Article  Google Scholar 

  32. 32.

    Morosan, D. E. et al. LOFAR tied-array imaging and spectroscopy of solar S bursts. Astron. Astrophys. 580, A65 (2015).

    Article  Google Scholar 

  33. 33.

    Long, D. M. et al. The kinematics of a globally propagating disturbance in the solar corona. Astrophys. J. Lett. 680, L81 (2008).

    ADS  Article  Google Scholar 

  34. 34.

    Grechnev, V. V. et al. Coronal shock waves, EUV waves, and their relation to CMEs. I. Reconciliation of EIT Waves, type II radio bursts, and leading edges of CMEs. Sol. Phys. 273, 433–460 (2011).

    ADS  Article  Google Scholar 

  35. 35.

    Zucca, P., Carley, E. P., Bloomfield, D. S. & Gallagher, P. T. The formation heights of coronal shocks from 2D density and Alfvén speed maps. Astron. Astrophys. 564, A47 (2014).

    ADS  Article  Google Scholar 

  36. 36.

    Bein, B. M. et al. Impulsive acceleration of coronal mass ejections. I. Statistics and coronal mass ejection source region characteristics. Astrophys. J. 738, 191 (2011).

    ADS  Article  Google Scholar 

  37. 37.

    Liu, Y. D. et al. Observations of an extreme storm in interplanetary space caused by successive coronal mass ejections. Nat. Commun. 5, 3481 (2014).

    Article  Google Scholar 

  38. 38.

    Liu, W. et al. Truly global extreme ultraviolet wave from the SOL2017-09-10 X8.2+ solar flare-coronal mass ejection. Astrophys. J. Lett. 864, L24 (2018).

    ADS  Article  Google Scholar 

  39. 39.

    Bemporad, A. & Mancuso, S. Super- and sub-critical regions in shocks driven by radio-loud and radio-quiet CMEs. J. Adv. Res. 4, 287–291 (2013).

    Article  Google Scholar 

  40. 40.

    Shen, C. et al. Strength of coronal mass ejection-driven shocks near the sun and their importance in predicting solar energetic particle events. Astrophys. J. 670, 849 (2007).

    ADS  Article  Google Scholar 

  41. 41.

    Mann, G., Melnik, V. N., Rucker, H. O., Konovalenko, A. A. & Brazhenko, A. I. Radio signatures of shock-accelerated electron beams in the solar corona. Astron. Astrophys. 609, A41 (2018).

    ADS  Article  Google Scholar 

  42. 42.

    Johlander, A. et al. Rippled quasiperpendicular shock observed by the magnetospheric multiscale spacecraft. Phys. Rev. Lett. 117, 165101 (2016).

    ADS  Article  Google Scholar 

  43. 43.

    Gingell, I. et al. MMS observations and hybrid simulations of surface ripples at a marginally quasi-parallel shock. J. Geophys. Res. 122, 11003 (2017).

    Article  Google Scholar 

  44. 44.

    Lembège, B. & Savoini, P. Formation of reflected electron bursts by the nonstationarity and nonuniformity of a collisionless shock front. J. Geophys. Res. 107, 1037 (2002).

    Article  Google Scholar 

  45. 45.

    Yang, Z., Lu, Q., Liu, Y. D. & Wang, R. Impact of shock front rippling and self-reformation on the electron dynamics at low-mach-number shocks. Astrophys. J. 857, 36 (2018).

    ADS  Article  Google Scholar 

  46. 46.

    Morgan, H. & Druckmüller, M. Multi-scale gaussian normalization for solar image processing. Sol. Phys. 289, 2945–2955 (2014).

    ADS  Article  Google Scholar 

  47. 47.

    GOES-R Series Solar Ultraviolet Imager (SUVI) Level 1b Product in FITS Format (NOAA, National Centers for Environmental Information, 2018);

  48. 48.

    Newkirk, G. Jr. The solar corona in active regions and the thermal origin of the slowly varying component of solar radio radiation. Astrophys. J. 133, 983 (1961).

    ADS  Article  Google Scholar 

  49. 49.

    Stappers, B. W. et al. Observing pulsars and fast transients with LOFAR. Astron. Astrophys. 530, A80 (2011).

    Article  Google Scholar 

  50. 50.

    Schrijver, C. J. & De Rosa, M. L. Photospheric and heliospheric magnetic fields. Sol. Phys. 212, 165–200 (2003).

    ADS  Article  Google Scholar 

  51. 51.

    Gallagher, P. T., Lawrence, G. R. & Dennis, B. R. Rapid acceleration of a coronal mass ejection in the low corona and implications for propagation. Astrophys. J. Lett. 588, L53–L56 (2003).

    ADS  Article  Google Scholar 

  52. 52.

    Zhao, M.-X., Le, G.-M. & Chi, Y.-T. Investigation of the possible source for solar energetic particle event of 2017 September 10. Res. Astron. Astrophys. 18, 7 (2018).

    ADS  Article  Google Scholar 

  53. 53.

    Kontar, E. P. et al. Imaging spectroscopy of solar radio burst fine structures. Nat. Commun. 8, 1515 (2017).

    ADS  Article  Google Scholar 

  54. 54.

    Condon, J. J. Errors in elliptical gaussian FITS. Publ. Astron. Soc. Pac. 109, 166 (1997).

    ADS  Article  Google Scholar 

  55. 55.

    Komesaroff, M. M. Ionospheric refraction in radio astronomy. I. Theory. Aust. J. Phys. 13, 153 (1960).

    ADS  Article  Google Scholar 

  56. 56.

    Stewart, R. T. & McLean, D. J. Correcting low-frequency solar radio source positions for ionospheric refraction. Proc. Astron. Soc. Aust. 4, 386–389 (1982).

    ADS  Article  Google Scholar 

  57. 57.

    Reinisch, B. W. & Galkin, I. A. Global ionospheric radio observatory (GIRO). Earth Planets Space 63, 377 (2011).

    ADS  Article  Google Scholar 

Download references


This paper is based (in part) on data obtained with the International LOFAR Telescope (ILT) under project code DDT8_005. LOFAR30 is the Low Frequency Array designed and constructed by ASTRON. It has observing, data processing, and data storage facilities in several countries, which are owned by various parties (each with their own funding sources), and are collectively operated by the ILT foundation under a joint scientific policy. The ILT resources have benefited from the following recent major funding sources: CNRS-INSU, Observatoire de Paris and Université d’Orléans, France; BMBF, MIWF-NRW, MPG, Germany; Science Foundation Ireland (SFI), Department of Business, Enterprise and Innovation (DBEI), Ireland; NWO, The Netherlands; and The Science and Technology Facilities Council, UK. I-LOFAR received funding from Science Foundation Ireland (SFI) grant no. 15/RI/3204. D.E.M. received external funding from the MET Office, Exeter, UK at Trinity College Dublin. E.P.C. is supported by the H2020 INFRADEV-1-2017 LOFAR4SW project no. 777442. L.A.H. is supported by Enterprise Partnership Scheme studentship from the Irish Research Council (IRC) between Trinity College Dublin and Adnet System Inc. S.A.M. is supported by the Irish Research Council Postdoctoral Fellowship Programme and the Air Force Office of Scientific Research award number FA9550-17-1-039. E.K.J.K. and D.E.M. acknowledge The Finnish Centre of Excellence in Research of Sustainable Space, funded through the Academy of Finland grant no. 1312390 and Academy of Finland Project 1310445. This project has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant no. 4100103, SolMAG). The authors would like to acknowledge NOAA’s National Centers for Environmental Information SUVI team for providing data on the September 2017 flares and M. Grandin for his advice in correcting for ionospheric effects.

Author information




D.E.M. performed the data analysis, interpretation of results and prepared the manuscript. E.P.C reconstructed the 3D model, contributed to the interpretation of results and manuscript preparation. L.A.H. produced the cartoon, contributed to the preparation of EUV images and interpretation of results. S.A.M. processed the EUV images and contributed to discussion of the results and manuscript preparation. P.Z. supplied the Alfvén speed maps and prepared the LOFAR core observation with the help of R.A.F. J.M. prepared and supplied the I-LOFAR observations. E.K.J.K. contributed to the interpretation of results and manuscript preparation. G.M and C.V were involved in the LOFAR observing proposal. P.T.G. is the PI of the LOFAR observing proposal and I-LOFAR project and guided the data analysis and writing of the manuscript.

Corresponding author

Correspondence to Diana E. Morosan.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Journal peer review information: Nature Astronomy thanks Iver Cairns, Silja Pohjolainen, Zhongwei Yang and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Publisher’s note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Video 1 caption, Supplementary Figures 1–5

Supplementary Video 1

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Morosan, D.E., Carley, E.P., Hayes, L.A. et al. Multiple regions of shock-accelerated particles during a solar coronal mass ejection. Nat Astron 3, 452–461 (2019).

Download citation

Further reading