Solar Physics

, 295:7 | Cite as

Peculiar Solar Sources and Geospace Disturbances on 20–26 August 2018

  • A. A. AbuninEmail author
  • M. A. Abunina
  • A. V. Belov
  • I. M. Chertok


On the approach to minimum of Solar Cycle 24, on 26 August 2018, an unexpectedly strong geomagnetic storm (GMS) suddenly occurred. Its \(D _{\mathit{st}}\) index reached \(-174~\mbox{nT}\), that is, the third most intense storm of the cycle. The analysis showed that it was initiated by a two-step long filament eruption, which occurred on 20 August in the central sector of the solar disk. The eruptions were accompanied by two large-scale divergent flare-like ribbons and dimmings of a considerable size and were followed by relatively weak but evident Earth-directed coronal mass ejections. In the inner corona, their estimated speed was very low, about \(200\mbox{--}360~\mbox{km}\,\mbox{s}^{-1}\). The respective interplanetary transients apparently propagated between two high-speed solar wind streams originated from a two-component coronal hole and therefore their expansion was limited. The resulting ejecta arrived at Earth only on 25 August and brought an unexpectedly strong field of \(B _{\mathit{t}} \approx 18.2~\mbox{nT}\) with a predominantly negative \(B _{\mathit{z}}\) component of almost the same strength. The geospace storm also manifested itself in the form of a peculiar Forbush decrease (FD). Its magnitude was about 1.5%, which is rather small for the observed G3-class GMS. The main unusual feature of the event is that large positive bursts with an enhancement up to 3% above the pre-event level were recorded on the FD background. We argue that these bursts were mainly caused by an unusually large and changeable cosmic ray anisotropy combined with lowering of the geomagnetic cutoff rigidity in the perturbed Earth’s magnetosphere under cycle minimum-like conditions.


Filament eruption Coronal mass ejection Geomagnetic storm Forbush decrease 



We are grateful to an anonymous reviewer for useful remarks and comments. The authors thank the BBSO, DSCOVR, GOES, SDO/AIA, SEED, SOHO/LASCO, STEREO-A/COR2, SWPC, NMDB, and other related teams for the open-access data used in this study. All data sources used in producing the results presented in this article are quoted in Sections 2 and 3. This research was partially supported by the Russian Foundation of Basic Research under grants 17-02-00308 and 18-52-34004, by the Russian Science Foundation under grant 15-12-20001, and by the Complex Program 19–270 of the Russian Ministry of Education and Science.

Disclosure of Potential Conflicts of Interest

The authors declare that they have no conflict of interest with publishing this research results in Solar Physics.


  1. Abunin, A.A., Abunina, M.A., Belov, A.V., Gaidash, S.P., Eroshenko, E.A., Pryamushkina, I.I., Trefilova, L.A., Gamza, E.I.: 2019, Database capabilities for studying Forbush-effects and interplanetary disturbances. J. Phys. Conf. Ser.1181, 012062. DOI. CrossRefGoogle Scholar
  2. Belov, A.V.: 2009, Forbush effects and their connection with solar, interplanetary and geomagnetic phenomena. In: Gopalswamy, N., Webb, D. (eds.) Universal Heliophysical Processes, Proc. IAU Symp.257, 439. DOI. CrossRefGoogle Scholar
  3. Belov, A., Eroshenko, E., Yanke, V., Oleneva, V., Abunin, A., Abunina, M., Papaioannou, A., Mavromichalaki, E.: 2018, The global survey method applied to ground level cosmic ray measurements. Solar Phys.293, 68. DOI. ADSCrossRefGoogle Scholar
  4. Brueckner, G.E., Howard, R.A., Koomen, M.J., Korendyke, C.M., Michels, D.J., Moses, J.D., et al.: 1995, The Large Angle Spectroscopic Coronagraph (LASCO). Solar Phys.162, 357. DOI. ADSCrossRefGoogle Scholar
  5. Cane, H.: 2000, Coronal mass ejections and Forbush decreases. Space Sci. Rev.93, 55. DOI. ADSCrossRefGoogle Scholar
  6. Chen, Ch., Liu, Y.D., Wang, R., Zhao, X., Hu, H., Zhu, B.: 2019, Characteristics of a gradual filament eruption and subsequent CME propagation in relation to a strong geomagnetic storm. Astrophys. J.884, 90. DOI. ADSCrossRefGoogle Scholar
  7. Chertok, I.M., Belov, A.V., Abunin, A.A.: 2018, Solar eruptions, Forbush decreases and geomagnetic disturbances from outstanding active region 12673. Space Weather16, 1549. DOI. ADSCrossRefGoogle Scholar
  8. Chertok, I.M., Grechnev, V.V., Belov, A.V., Abunin, A.A.: 2013, Magnetic flux of EUV arcade and dimming regions as a relevant parameter for early diagnostics of solar eruptions – Sources of non-recurrent geomagnetic storms and Forbush decreases. Solar Phys.282, 175. DOI. ADSCrossRefGoogle Scholar
  9. Cohen, C.M.S., Mewaldt, R.A.: 2018, The ground level enhancement event of September 2017 and other large solar energetic particle events of cycle 24. Space Weather16, 1616. DOI. ADSCrossRefGoogle Scholar
  10. Domingo, V., Fleck, B., Poland, A.I.: 1995, The SOHO mission: An overview. Solar Phys.162, 1. DOI. ADSCrossRefGoogle Scholar
  11. Dorman, L.: 2009, Cosmic Rays in Magnetosphere of Earth and Planets, Astrophys. and Space Sci. Library358, Springer, Berlin. DOI, 770 pp. CrossRefGoogle Scholar
  12. Evenson, P., Mangeard, P.S., Muangha, P., Pyle, R., Ruffolo, D., Sáiz, A. (IceCube Collaboration): 2017, Impulsive increase of galactic cosmic ray flux observed by IceTop. In: Proc. of the 35th International. Cosmic Ray Conf., 10–20 July, 2017, Bexco, Busan, Korea. Proc. of Science301, 133. Google Scholar
  13. Gil, A., Kovaltsov, G.A., Mikhailov, V.V., Mishev, A., Poluianov, S., Usoskin, I.G.: 2018, An anisotropic cosmic-ray enhancement event on 07-June-2015: A possible origin. Solar Phys.293, 154. DOI. ADSCrossRefGoogle Scholar
  14. Gopalswamy, N., Tsurutani, B., Yan, Y.: 2015, Short-term variability of the Sun–Earth system: An overview of progress made during the CAWSES-II period. Prog. Earth Planet. Sci.2, 13. DOI. ADSCrossRefGoogle Scholar
  15. Gopalswamy, N., Akiyama, S., Yashiro, S., Xie, H., Mäkelä, P., Michalek, G.: 2014, Anomalous expansion of coronal mass ejections during solar cycle 24 and its space weather implications. Geophys. Res. Lett.41, 2673. DOI. ADSCrossRefGoogle Scholar
  16. Gopalswamy, N., Yashiro, S., Mäkelä, P., Xie, H., Akiyama, S., Monstein, C.: 2018, Extreme kinematics of the 2017 September 10 solar eruption and the spectral characteristics of the associated energetic particles. Astrophys. J. Lett.863, L39. DOI. ADSCrossRefGoogle Scholar
  17. Grechnev, V.V., Uralov, A.M., Chertok, I.M., Belov, A.V., Filippov, B.P., Slemzin, V.A., Jackson, B.V.: 2014, A challenging solar eruptive event of 18 November 2003 and the causes of the 20 November geomagnetic superstorm. IV. Unusual magnetic cloud and overall scenario. Solar Phys.289, 4653. DOI. ADSCrossRefGoogle Scholar
  18. Hou, Y.J., Zhang, J., Li, T., Yang, S.H., Li, X.H.: 2018, Eruption of a multi-flux-rope system in solar active region 12673 leading to the two largest flares in solar cycle 24. Astron. Astrophys.619, A100. DOI. ADSCrossRefGoogle Scholar
  19. Howard, R.A., Moses, J.D., Vourlidas, A., Newmark, J.S., Socker, D.G., Plunkett, S.P., et al.: 2008, Sun Earth Connection and Heliospheric Investigation (SECCHI). Space Sci. Rev.136, 67. DOI. ADSCrossRefGoogle Scholar
  20. Kaiser, M.L., Kucera, T.A., Davila, J.M., St. Cyr, O.C., Guhathakurta, M., Christian, E.: 2008, The STEREO mission: An introduction. Space Sci. Rev.136, 5. DOI. ADSCrossRefGoogle Scholar
  21. Kumar, A., Badruddin: 2014, Interplanetary coronal mass ejections, associated features, and transient modulation of galactic cosmic rays. Solar Phys.289, 2177. DOI. ADSCrossRefGoogle Scholar
  22. Kuwabara, T., Bieber, J.W., Clem, J., Evenson, P., Pyle, R., Munakata, K., et al.: 2006, Real-time cosmic ray monitoring system for space weather. Space Weather4, S08001. DOI. ADSCrossRefGoogle Scholar
  23. Lemen, J.R., Title, A.M., Akin, D.J., Boerner, P.F., Chou, C., Drake, J.F., et al.: 2012, The Atmospheric Imaging Assembly (AIA) on the Solar Dynamics Observatory (SDO). Solar Phys.275, 17. DOI. ADSCrossRefGoogle Scholar
  24. Manchester, W. IV, Kilpua, E.K.J., Liu, Y.D., Lugaz, N., Riley, P., Török, T., Vršnak, B.: 2017, The physical processes of CME/ICME evolution. Space Sci. Rev.212, 1159. DOI. ADSCrossRefGoogle Scholar
  25. Manoharan, P.K.: 2010, Ooty interplanetary scintillation – Remote-sensing observations and analysis of coronal mass ejections in the heliosphere. Solar Phys.265, 137. DOI. ADSCrossRefGoogle Scholar
  26. Manoharan, P.K., Mahalakshmi, K., Johri, A., Jackson, B.V., Ravikumar, D., Kalyanasundaram, K., et al.: 2018, Current state of reduced solar activity: Intense geomagnetic storms. Sun Geosph.13, 135. DOI. ADSCrossRefGoogle Scholar
  27. Mishra, S.K., Srivastava, A.K.: 2019, Linkage of geoeffective stealth CMEs associated with the eruption of coronal plasma channel and jet-like structure. Solar Phys.294, 169. DOI. ADSCrossRefGoogle Scholar
  28. Munakata, K., Kuwabara, T., Yasue, S., Kato, C., Akahane, S., Koyama, M., et al.: 2005, A “loss cone” precursor of an approaching shock observed by a cosmic ray muon hodoscope on October 28, 2003. Geophys. Res. Lett.32, L03S04. DOI. CrossRefGoogle Scholar
  29. Munakata, K., Kozai, M., Evenson, P., Kuwabara, T., Kato, C., Tokumaru, M., et al.: 2018, Cosmic-ray short burst observed with the Global Muon Detector Network (GMDN) on June 22, 2015. Astrophys. J.862, 170. DOI. ADSCrossRefGoogle Scholar
  30. Papailiou, M., Mavromichalaki, H., Belov, A., Eroshenko, E., Yanke, V.: 2012, Precursor effects in different cases of Forbush decreases. Solar Phys.276, 337. DOI. ADSCrossRefGoogle Scholar
  31. Pesnell, W.D., Thompson, B.J., Chamberlin, P.C.: 2012, The Solar Dynamics Observatory (SDO). Solar Phys.275, 3. DOI. ADSCrossRefGoogle Scholar
  32. Samara, E., Smponias, A., Lytrosyngounis, I., Lingri, D., Mavromichalaki, H., Sgouropoulos, C.: 2018, Unusual cosmic ray variations during the Forbush decreases of June 2015. Solar Phys.293, 67. DOI. ADSCrossRefGoogle Scholar
  33. Verma, M.: 2018, On the origin of two X-class flares in active region NOAA 12673 – Shear flows and head-on collision of new and pre-existing flux. Astron. Astrophys.612, A101. DOI. ADSCrossRefGoogle Scholar
  34. Vial, J.-C., Engvold, O. (eds.): 2015, Solar Prominences. Astrophys. Space Sci. Library415, Springer, Basel. DOI. 487 pp. CrossRefGoogle Scholar
  35. Watari, S.: 2017, Geomagnetic storms of cycle 24 and their solar sources. Earth Planets Space69, 70. DOI. ADSCrossRefGoogle Scholar
  36. Webb, D., Howard, T.A.: 2012, Coronal mass ejections: Observations. Living Rev. Solar Phys.9, 3. DOI. ADSCrossRefGoogle Scholar
  37. Yang, S., Zhang, J., Zhu, X., Song, O.: 2017, Block-induced complex structures building the flare-productive solar active region 12673. Astrophys. J. Lett.849, L21. DOI. ADSCrossRefGoogle Scholar

Copyright information

© Springer Nature B.V. 2020

Authors and Affiliations

  1. 1.Pushkov Institute of Terrestrial MagnetismIonosphere and Radio Wave Propagation (IZMIRAN)MoscowRussia
  2. 2.Kalmyk State UniversityElistaRussia

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