Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

Relationship Between Solar-Wind Speed and Coronal Magnetic-Field Properties


We have studied the relationship between the solar-wind speed \([V]\) and the coronal magnetic-field properties (a flux-expansion factor [\(f\)] and photospheric magnetic-field strength [\(B_{\mathrm{S}}\)]) at all latitudes using data of interplanetary scintillation and solar magnetic field obtained for 24 years from 1986 to 2009. Using a cross-correlation analyses, we verified that \(V\) is inversely proportional to \(f\) and found that \(V\) tends to increase with \(B_{\mathrm{S}}\) if \(f\) is the same. As a consequence, we find that \(V\) has an extremely good linear correlation with \(B_{\mathrm{S}}/f\). However, this linear relation of \(V\) and \(B_{\mathrm{S}}/f\) cannot be used for predicting the solar-wind velocity without information on the solar-wind mass flux. We discuss why the inverse relation between \(V\) and \(f\) has been successfully used for solar-wind velocity prediction, even though it does not explicitly include the mass flux and magnetic-field strength, which are important physical parameters for solar-wind acceleration.

This is a preview of subscription content, log in to check access.

Figure 1
Figure 2
Figure 3
Figure 4
Figure 5
Figure 6
Figure 7
Figure 8
Figure 9
Figure 10
Figure 11


  1. Altschuler, M.D., Newkirk, G.: 1969, Magnetic fields and the structure of the solar corona. I: methods of calculating coronal fields. Solar Phys. 9, 131. DOI .

  2. Arge, C.N., Pizzo, V.J.: 2000, Improvement in the prediction of solar wind conditions using near-real time solar magnetic field updates. J. Geophys. Res. 105, 10465. DOI .

  3. Fisk, L.A.: 2003, Acceleration of the solar wind as a result of the reconnection of open magnetic flux with coronal loops. J. Geophys. Res. 108, 1157. DOI .

  4. Fisk, L.A., Schwadron, N.A., Zurbuchen, T.H.: 1999, Acceleration of the fast solar wind by the emergence of new magnetic flux. J. Geophys. Res. 104, 19765. DOI .

  5. Hakamada, K., Kojima, M.: 1999, Solar wind speed and expansion rate of the coronal magnetic field during Carrington Rotation 1909. Solar Phys. 187, 115. DOI .

  6. Hirano, M., Kojima, M., Tokumaru, M., Fujiki, K., Ohmi, T., Yamashita, M., Hakamada, K., Hayashi, K.: 2003, The relation between the solar wind velocity and the magnetic conditions of coronal holes. In: AGU Fall Meeting Abstracts. B164.

  7. Kojima, M., Kakinuma, T.: 1990, Solar cycle dependence of global distribution of solar wind speed. Space Sci. Rev. 53, 173. DOI .

  8. Kojima, M., Tokumaru, M., Watanabe, H., Yokobe, A., Asai, K., Jackson, B.V., Hick, P.L.: 1998, Heliospheric tomography using interplanetary scintillation observations 2. Latitude and heliocentric distance dependence of solar wind structure at 0.1 – 1 AU. J. Geophys. Res. 103, 1981. DOI .

  9. Kojima, M., Fujiki, K., Hirano, M., Tokumaru, M., Ohmi, T., Hakamada, K.: 2004, Solar wind properties from IPS observations. In: Poletto, G., Suess, S.T. (eds.) The Sun and the Heliosphere as an Integrated System, Astrophys. Space Science Lib. 317, Springer, Heidelberg 147.

  10. Kojima, M., Tokumaru, M., Fujiki, K., Itoh, H., Murakami, T., Hakamada, K.: 2007, What coronal parameters determine solar wind speed? In: Shibata, K., Nagata, S., Sakurai, T. (eds.) New Solar Physics with Solar-B Mission 369, Astron. Soc. Pacific, San Francisco 549.

  11. McComas, D.J., Ebert, R.W., Elliott, H.A., Goldstein, B.E., Gosling, J.T., Schwadron, N.A., Skoug, R.M.: 2008, Weaker solar wind from the polar coronal holes and the whole Sun. Geophys. Res. Lett. 35, 18103. DOI .

  12. Ohmi, T., Kojima, M., Yokobe, A., Tokumaru, M., Fujiki, K., Hakamada, K.: 2001, Polar low-speed solar wind at the solar activity maximum. J. Geophys. Res. 106, 24923. DOI .

  13. Schatten, K.H., Wilcox, J.M., Ness, N.F.: 1969, A model of interplanetary and coronal magnetic fields. Solar Phys. 6, 442. DOI .

  14. Suzuki, T.K.: 2006, Forecasting solar wind speeds. Astrophys. J. Lett. 640, L75. DOI .

  15. Suzuki, T.K., Inutsuka, S.-i.: 2005, Making the corona and the fast solar wind: a self-consistent simulation for the low-frequency Alfvén waves from the photosphere to 0.3 AU. Astrophys. J. Lett. 632, L49. DOI .

  16. Tokumaru, M., Kojima, M., Fujiki, K., Hayashi, K.: 2009, Non-dipolar solar wind structure observed in the cycle 23/24 minimum. Geophys. Res. Lett. 36, 9101. DOI .

  17. von Steiger, R., Zurbuchen, T.H.: 2011, Polar coronal holes during the past solar cycle: Ulysses observations. J. Geophys. Res. 116, 1105. DOI .

  18. Wang, Y.-M.: 2010, On the relative constancy of the solar wind mass flux at 1 AU. Astrophys. J. Lett. 715, L121. DOI .

  19. Wang, Y.-M., Hawley, S.H., Sheeley, N.R. Jr.: 1996, The magnetic nature of coronal holes. Science 271, 464. DOI .

  20. Wang, Y.-M., Robbrecht, E., Sheeley, N.R. Jr.: 2009, on the weakening of the polar magnetic fields during solar cycle 23. Astrophys. J. 707, 1372. DOI .

  21. Wang, Y.-M., Sheeley, N.R. Jr.: 1990, Solar wind speed and coronal flux-tube expansion. Astrophys. J. 355, 726. DOI .

  22. Wang, Y.-M., Sheeley, N.R. Jr.: 1991, Why fast solar wind originates from slowly expanding coronal flux tubes. Astrophys. J. Lett. 372, L45. DOI .

  23. Wang, Y.-M., Sheeley, N.R. Jr.: 2013, The solar wind and interplanetary field during very low amplitude sunspot cycles. Astrophys. J. 764, 90. DOI .

Download references


The IPS observations were carried out under the solar-wind program of the Solar-Terrestrial Environment Laboratory (STEL) of Nagoya University, and were partially supported by the IUGONET Project of MEXT, Japan. The authors would like to express their thanks for the use of the NSO/Kitt Peak magnetogram data. They are also indebted to the NASA/GSFC’s Space Physics Data Facility’s OMNIweb service, and OMNI data. This work was carried out by the joint research program of the STEL, Nagoya University, and was also partially supported by the JSPS Grant-in-Aid for Scientific Research A (25257079).

Author information

Correspondence to Ken’ichi Fujiki.

Ethics declarations

Disclosure of Potential Conflicts of Interest

The authors declare that they have no conflict of interest.

Additional information

Radio Heliophysics: Science and Forecasting

Guest Editors: Mario M. Bisi, Bernard V. Jackson, and J. Americo Gonzalez-Esparza

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Fujiki, K., Tokumaru, M., Iju, T. et al. Relationship Between Solar-Wind Speed and Coronal Magnetic-Field Properties. Sol Phys 290, 2491–2505 (2015).

Download citation


  • Solar Wind
  • Radio Scintillation
  • Corona
  • Coronal Holes
  • Magnetic fields
  • Photosphere