Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Solar flare effects in the Earth’s magnetosphere


The Earth’s magnetosphere is the outermost layer of the geospace system deflecting energetic charged particles from the Sun and solar wind. The solar wind has major impacts on the Earth’s magnetosphere, but it is unclear whether the same holds for solar flares—a sudden eruption of electromagnetic radiation on the Sun. Here we use a recently developed whole geospace model combined with observational data from the 6 September 2017 X9.3 solar flare event to reveal solar flare effects on magnetospheric dynamics and on the electrodynamic coupling between the magnetosphere and its adjacent ionosphere, the ionized part of Earth’s upper atmosphere. We observe a rapid and large increase in flare-induced photoionization of the polar ionospheric E-region at altitudes between 90 km and 150 km. This reduces the efficiency of mechanical energy conversion in the dayside solar wind–magnetosphere interaction, resulting in less Joule heating of the Earth’s upper atmosphere, a reconfiguration of magnetosphere convection, as well as changes in dayside and nightside auroral precipitation. This work thus demonstrates that solar flare effects extend throughout the geospace via electrodynamic coupling, and are not limited—as previously believed—to the atmospheric region where radiation energy is absorbed1.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Fig. 1: Solar flare effects on the ionosphere.
Fig. 2: Solar flare effects on FACs and conductances in the Northern Hemisphere.
Fig. 3: Solar flare effects on magnetospheric convection and ionospheric potential.
Fig. 4: Time series of system parameters.

Data availability

Source data are provided with this paper. All other used data are available from the corresponding author upon reasonable request. The GNSS TEC and AMPERE FACs datasets are available from and EISCAT radar and Inuvik high-frequency radar data are available from and, respectively. THEMIS data are available from OMNI solar wind data are available from the CDAWeb website ( Solar irradiance data are provided by the NOAA National Geophysical Data Center (NGDC) GOES website (

Code availability

The computer code (LTR) to simulate the geospace response to solar flares is available from the corresponding author upon request.


  1. 1.

    Tsurutani, B. T. et al. A brief review of ‘solar flare effects’ on the ionosphere. Radio Sci. 44, RS0A17 (2009).

    Google Scholar 

  2. 2.

    Liu, J. Y. et al. Solar flare signatures of the ionospheric GPS total electron content. J. Geophys. Res. 111, A05308 (2006).

    ADS  Google Scholar 

  3. 3.

    Le, H., Ren, Z., Liu, L., Chen, Y. & Zhang, H. Global thermospheric disturbances induced by a solar flare: a modeling study. Earth Planets Space 67, 3 (2015).

    ADS  Google Scholar 

  4. 4.

    Liu, H., Lühr, H., Watanabe, S., Köhler, W. & Manoj, C. Contrasting behavior of the thermosphere and ionosphere in response to the 28 October 2003 solar flare. J. Geophys. Res. 112, A07305 (2007).

    ADS  Google Scholar 

  5. 5.

    Sutton, E. K., Forbes, J. M., Nerem, R. S. & Woods, T. N. Neutral density response to the solar flares of October and November, 2003. Geophys. Res. Lett. 33, L22101 (2006).

    ADS  Google Scholar 

  6. 6.

    Qian, L., Burns, A. G., Chamberlin, P. C. & Solomon, S. C. Variability of thermosphere and ionosphere responses to solar flares. J. Geophys. Res. 116, A10309 (2011).

    ADS  Google Scholar 

  7. 7.

    Zhang, D. H. et al. Impact factor for the ionospheric total electron content response to solar flare irradiation. J. Geophys. Res. 116, A04311 (2011).

    ADS  Google Scholar 

  8. 8.

    Pembroke, A. et al. Initial results from a dynamic coupled magnetosphere-ionosphere-ring current model. J. Geophys. Res. 117, A02211 (2012).

    ADS  Google Scholar 

  9. 9.

    Glocer, A. et al. CRCM + BATS-R-US two-way coupling. J. Geophys. Res. 118, 1635–1650 (2013).

    Google Scholar 

  10. 10.

    Lyon, J. G., Fedder, J. A. & Mobarry, C. M. The Lyon–Fedder–Mobarry (LFM) global MHD magnetospheric simulation code. J. Atmos. Sol. Terr. Phys. 66, 1333–1350 (2004).

    ADS  Google Scholar 

  11. 11.

    De Zeeuw, D. L. et al. Coupling of a global MHD code and an inner magnetospheric model: initial results. J. Geophys. Res. 109, A12219 (2004).

    ADS  Google Scholar 

  12. 12.

    Berdermann, J. et al. Ionospheric response to the X9.3 flare on 6 September 2017 and its implication for navigation services over Europe. Space Weather 16, 1604–1615 (2018).

    ADS  Google Scholar 

  13. 13.

    Qian, L. et al. Solar flare and geomagnetic storm effects on the thermosphere and ionosphere during 6–11 September 2017. J. Geophys. Res. 124, 2298–2311 (2019).

    Google Scholar 

  14. 14.

    Yamauchi, M. et al. Ionospheric response observed by EISCAT during the 6–8 September 2017 space weather event: overview. Space Weather 16, 1437–1450 (2018).

    ADS  Google Scholar 

  15. 15.

    Ridley, A., Gombosi, T. & Dezeeuw, D. Ionospheric control of the magnetosphere: conductance. Ann. Geophys. 22, 567–584 (2004).

    ADS  Google Scholar 

  16. 16.

    Wiltberger, M., Weigel, R. S., Lotko, W. & Fedder, J. A. Modeling seasonal variations of auroral particle precipitation in a global-scale magnetosphere-ionosphere simulation. J. Geophys. Res. 114, A01204 (2009).

    ADS  Google Scholar 

  17. 17.

    Merkin, V. G. et al. Global evolution of Birkeland currents on 10 min timescales: MHD simulations and observations. J. Geophys. Res. 118, 4977–4997 (2013).

    Google Scholar 

  18. 18.

    Borovsky, J. E., Lavraud, B. & Kuznetsova, M. M. Polar cap potential saturation, dayside reconnection, and changes to the magnetosphere. J. Geophys. Res. 114, A03224 (2009).

    ADS  Google Scholar 

  19. 19.

    Lotko, W. et al. Ionospheric control of magnetotail reconnection. Science 345, 184–187 (2014).

    ADS  Google Scholar 

  20. 20.

    Förster, M., Doornbos, E. & Haaland, S. in Dawn–Dusk Asymmetries in Planetary Plasma Environments (eds Haaland, S. et al.) Ch. 10, 125–142 (Geophysical Monograph Series, John Wiley Publications, 2017).

  21. 21.

    Paschmann, G. et al. Plasma acceleration at the Earth’s magnetopause: evidence for magnetic reconnection. Nature 282, 243–246 (1979).

    ADS  Google Scholar 

  22. 22.

    Chen, L. et al. Electron bulk acceleration and thermalization at Earth’s quasiperpendicular bow shock. Phys. Rev. Lett. 120, 225101 (2018).

    ADS  Google Scholar 

  23. 23.

    Fedder, J. A. & Lyon, J. G. The solar wind-magnetosphere-ionosphere current-voltage relationship. Geophys. Res. Lett. 14, 880–883 (1987).

    ADS  Google Scholar 

  24. 24.

    Kozyra, J. U. et al. Effects of a high-density plasma sheet on ring current development during the November 2–6, 1993, magnetic storm. J. Geophys. Res. 103, 26285–26305 (1998).

    ADS  Google Scholar 

  25. 25.

    Turner, N. E., Cramer, W. D., Earles, S. K. & Emery, B. A. Geoefficiency and energy partitioning in CIR-driven and CME-driven storms. J. Atmos. Sol. Terr. Phys. 71, 1023–1031 (2009).

    ADS  Google Scholar 

  26. 26.

    Clausen, L. B. N., Baker, J. B. H., Ruohoniemi, J. M., Milan, S. E. & Anderson, B. J. Dynamics of the region 1 Birkeland current oval derived from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE). J. Geophys. Res. 117, A06233 (2012).

    ADS  Google Scholar 

  27. 27.

    Roble, R. G., Ridley, E. C., Richmond, A. D. & Dickinson, R. E. A coupled thermosphere/ionosphere general circulation model. Geophys. Res. Lett. 15, 1325–1328 (1988).

    ADS  Google Scholar 

  28. 28.

    Richmond, A. D., Ridley, E. C. & Roble, R. G. A thermosphere/ionosphere general circulation model with coupled electrodynamics. Geophys. Res. Lett. 19, 601–604 (1992).

    ADS  Google Scholar 

  29. 29.

    Toffoletto, F., Sazykin, S., Spiro, R. & Wolf, R. Inner magnetospheric modeling with the Rice Convection Model. Space Sci. Rev. 107, 175–196 (2003).

    ADS  Google Scholar 

  30. 30.

    Merkin, V. G. & Lyon, J. G. Effects of the low-latitude ionospheric boundary condition on the global magnetosphere. J. Geophys. Res. 115, A10202 (2000).

    ADS  Google Scholar 

  31. 31.

    Wang, W. et al. Initial results from the coupled magnetosphere–ionosphere–thermosphere model: thermosphere–ionosphere responses. J. Atmos. Sol. Terr. Phys. 66, 1425–1441 (2004).

    ADS  Google Scholar 

  32. 32.

    Lin, D. et al. SAPS in the 17 March 2013 storm event: initial results from the coupled magnetosphere–ionosphere–thermosphere model. J. Geophys. Res. 124, 6212–6225 (2019).

    Google Scholar 

  33. 33.

    Wang, W. et al. Ionospheric electric field variations during a geomagnetic storm simulated by a coupled magnetosphere ionosphere thermosphere (CMIT) model. Geophys. Res. Lett. 35, L18105 (2008).

    ADS  Google Scholar 

  34. 34.

    Zhang, B. et al. Electron precipitation models in global magnetosphere simulations. J. Geophys. Res. 120, 1035–1056 (2015).

    Google Scholar 

  35. 35.

    Cnossen, I. & Förster, M. North–south asymmetries in the polar thermosphere-ionosphere system: solar cycle and seasonal influences. J. Geophys. Res. 121, 612–627 (2016).

    Google Scholar 

  36. 36.

    Chamberlin, P. C., Woods, T. N. & Eparvier, F. G. Flare Irradiance Spectral Model (FISM): daily component algorithms and results. Space Weather 5, S05001 (2007).

    Google Scholar 

  37. 37.

    Chamberlin, P. C., Woods, T. N. & Eparvier, F. G. Flare Irradiance Spectral Model (FISM): flare component algorithms and results. Space Weather 6, S05001 (2008).

    ADS  Google Scholar 

  38. 38.

    Woods, T. N. et al. The Solar EUV Experiment (SEE): mission overview and first results. J. Geophys. Res. 110, A01312 (2005).

    ADS  Google Scholar 

  39. 39.

    Solomon, S. C. & Qian, L. Solar extreme-ultraviolet irradiance for general circulation models. J. Geophys. Res. 110, A10306 (2005).

    ADS  Google Scholar 

  40. 40.

    Coster, A. & Komjathy, A. Space weather and the global positioning system. Space Weather 6, S06D04 (2008).

    Google Scholar 

  41. 41.

    Lotko, W. The unifying principle of coordinated measurements in geospace science. Space Weather 15, 553–557 (2017).

    ADS  Google Scholar 

  42. 42.

    Anderson, B. J. et al. Development of large-scale Birkeland currents determined from the Active Magnetosphere and Planetary Electrodynamics Response Experiment. Geophys. Res. Lett. 41, 3017–3025 (2014).

    ADS  Google Scholar 

  43. 43.

    Shepherd, S. G. Altitude-adjusted corrected geomagnetic coordinates: definition and functional approximations. J. Geophys. Res. 119, 7501–7521 (2014).

    Google Scholar 

  44. 44.

    Knipp, D. et al. Comparison of magnetic perturbation data from LEO satellite constellations: statistics of DMSP and AMPERE. Space Weather 12, 2–23 (2014).

    ADS  Google Scholar 

Download references


This work is supported by the Strategic Priority Research Program of Chinese Academy of Sciences grant no. XDB 41000000, NSF of China 42074188 and 42030202, and US NSF Awards 1739188, 1522133 and AGS1452309. We acknowledge the use of data from the Chinese Meridian Project. We thank Q. Shi and W. Shang for helpful discussions.

Author information




J.L. led the study, collected data and analysed the results. J.L., W. Wang, L.Q. and A.G.B. prepared the manuscript. W.L. contributed interpretations, writing and editing. K.P. analysed the model results. G.L., S.C.S., L.L. and W. Wan participated in writing and revising the paper. B.J.A. and A.C. were responsible for verification of the AMPERE FACs and GNSS TEC data, respectively. F.W. contributed to analysing the THEMIS data.

Corresponding author

Correspondence to Jing Liu.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Physics thanks Matthias Förster 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.

Extended data

Extended Data Fig. 1 Interplanetary solar wind parameters and x-ray intensity.

a, Interplanetary magnetic field components, Bx, By, and Bz in nT; b, solar wind number density in cm−3; c, solar wind velocity components, Vx, Vy, and Vz in km/s; and (d) X-ray intensity on September 6, 2017 integrated over wavelengths from 0.1 to 0.8 nm observed by the GOES satellite (red line), calculated from FISM (blue line), and without solar flare effects (black line). Horizontal dotted lines represent zero Y-axis reference lines in panels a and c.

Extended Data Fig. 2 Solar flare effects on the polar ionosphere.

Universal time and altitude variations of electron density (Ne), electron temperature (Te), and ion temperature (Ti) from LTR flare simulations (left panels) and EISCAT Tromsø VHF radar (right panels) on 6 September 2017. Since the VHF radar was pointing at geographic north with 30° elevation angle, the latitudinal coverage is about 69°–72° for 80–400 km altitude.

Source data

Extended Data Fig. 3 LTR-simulated Hall conductance ∑H for pre-flare and flare-peak intervals.

Comparison of 10-minute average LTR simulated Hall ∑H conductance for pre-flare (11:44–11:53 UT, a, flare-peak (12:10–12:19 UT, b, intervals on September 6, 2017. Polar plots are in magnetic latitude-local time (MLT) coordinates as in panel a.

Source data

Extended Data Fig. 4 Spacecraft measurements from THEMIS TH-A and TH-E.

From top to bottom are magnitude of magnetic field a, e, ion density b, f, bulk flow c, g, and ion spectra d, h. The four horizontal axes in the bottom panels stand for X (Xgsm), Y (Ygsm), and Z (Zgsm) components in the Geocentric Solar Magnetospheric System coordinate, and universal time (UT).

Supplementary information

Supplementary Software

MATLAB code to virtualize source data.

Source data

Source Data Fig. 1

Numerical simulated TEC used to generate Fig. 1.

Source Data Fig. 2

Numerical simulated FACs used to generate Fig. 2.

Source Data Fig. 3

Numerical simulated velocity used to generate Fig. 3.

Source Data Fig. 4

Numerical simulated CPCP and Joule heating rate used to generate Fig. 4.

Source Data Extended Data Fig. 2

Numerical simulated Ne, Te and Ti used to generate Extended Data Fig. 2.

Source Data Extended Data Fig. 3

Numerical simulated Hall conductance used to generate Extended Data Fig. 3.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Liu, J., Wang, W., Qian, L. et al. Solar flare effects in the Earth’s magnetosphere. Nat. Phys. 17, 807–812 (2021).

Download citation


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing