The solar wind is an extended ionized gas of very high electrical conductivity, and therefore drags some magnetic flux out of the Sun to fill the heliosphere with a weak interplanetary magnetic field1,2. Magnetic reconnection—the merging of oppositely directed magnetic fields—between the interplanetary field and the Earth's magnetic field allows energy from the solar wind to enter the near-Earth environment. The Sun's properties, such as its luminosity, are related to its magnetic field, although the connections are still not well understood3,4. Moreover, changes in the heliospheric magnetic field have been linked with changes in total cloud cover over the Earth, which may influence global climate5. Here we show that measurements of the near-Earth interplanetary magnetic field reveal that the total magnetic flux leaving the Sun has risen by a factor of 1.4 since 1964: surrogate measurements of the interplanetary magnetic field indicate that the increase since 1901 has been by a factor of 2.3. This increase may be related to chaotic changes in the dynamo that generates the solar magnetic field. We do not yet know quantitatively how such changes will influence the global environment.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Tax calculation will be finalised during checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
Gazis, P. R. Solar cycle variation of the heliosphere. Rev. Geophys. 34, 379–402 (1996).
Balogh, A.et al. The heliospheric field over the south polar region of the sun. Science 268, 1007–1010 (1995).
Willson, R. C. Total solar irradiance trend during cycles 21 and 22. Science 277, 1963–1965 (1997).
Lean, J., Beer, J. & Bradley, R. Reconstruction of solar irradiance since 1610: implications for climate change. Geophys. Res. Lett. 22, 3195–3198 (1995).
Svensmark, H. & Friis-Christensen, E. Variation of cosmic ray flux and global cloud coverage—a missing link in solar-climate relationships. J. Atmos. Sol. Terr. Phys. 59, 1225–1232 (1997).
Mayaud, P. N. The aa indices: a 100-year series characterising the magnetic activity. J. Geophys. Res. 72, 6870–6874 (1972).
Stamper, R., Lockwood, M., Wild, M. N. & Clark, T. D. G. Solar causes of the long-term increase in geomagnetic activity. J. Geophys. Res.(in press).
Russell, C. T. On the possibility of deducing interplanetary and solar parameters from geomagnetic records. Sol. Phys. 42, 259–269 (1975).
Gringauz, K. I. in Solar Wind 4(ed. Rosenbauer, H.) (Rep. MPAE-W-100-81-31, MPI für Aeronomie, Lindau, Germany, (1981).
Feynman, J. & Crooker, N. U. The solar wind at the turn of the century. Nature 275, 626–627 (1978).
Baker, D. in Solar Wind-Magnetosphere Coupling(eds Kamide, Y. & Slavin, J. A.) 17–38 (Terra Scientific, Tokyo, (1986).
Wang, Y.-M. & Sheeley, N. R. J Solar implications of Ulysses interplanetary field measurements. Astrophys. J. 447, L143–L146 (1995).
Cliver, E. W., Boriakoff, V. & Bounar, K. H. The 22-year cycle of geomagnetic activity. J. Geophys. Res. 101, 27091–27109 (1996).
Silverman, S. W. Secular variation of the aurora for the past 500 years. Rev. Geophys. 30, 333–351 (1992).
Sonnet, C. P. Long-period solar terrestrial variability. Rev. Geophys. (Suppl.: US Nat. Rep. to IUGG 1987–1990 909–914 (1991).
Beer, J., Tobias, S. & Weiss, N. An active sun throughout the Maunder minimum. Sol. Phys. 181, 237–249 (1998).
Feynman, J. & Gabriel, S. B. Period and phase of the 88-year solar cycle and the Maunder minimum: evidence for the chaotic sun. Sol. Phys. 127, 393–403 (1990).
Cliver, E. W., Boriakoff, V. & Feynman, J. Solar variability and climate change: geomagnetic aa index and global surface temperature. Geophys. Res. Lett. 25, 1035–1038 (1998).
Vasyliunas, V. M., Kan, J. R., Siscoe, G. L. & Akasofu, S.-I. Scaling relations governing magnetospheric energy transfer. Planet Space Sci. 30, 359–365 (1982).
Scurry, L. & Russell, C. T. Proxy studies of energy transfer to the magnetosphere. J. Geophys. Res. 96, 9541–9548 (1991).
Merrill, R. T., McElhinny, M. W. & McFadden, P. L. The Magnetic Field of the Earth 34 (Academic, San Diego, (1996).
Wang, Y.-M., Hawley, S. H. & Sheeley, N. R. J The magnetic nature of coronal holes. Science 271, 464–469 (1996).
Sargent, H. H. in Solar Wind-Magnetosphere Coupling(eds Kamide, Y. & Slavin, J. A.) 143–148 (Terra Scientific, Tokyo, (1986).
Hapgood, M. A. Adouble solar-cycle variation in the 27-day recurrence of geomagnetic activity. Ann Geophys. 11, 248–253 (1993).
Webb, D. F. & Howard, R. A. The solar cycle variation of coronal mass ejections and solar wind mass flux. J. Geophys. Res. 99, 4201–4220 (1994).
The data used are stored and made available via World Data Centre C1 for STP at RAL, which is funded by the UK Particle Physics and Astronomy Research Council and, until 1 April 1999, by the National Radio Propagation Programme of the Radiocommunications Agency. We also thank the many scientists who have contributed data to the WDC.
About this article
Cite this article
Lockwood, M., Stamper, R. & Wild, M. A doubling of the Sun's coronal magnetic field during the past 100 years. Nature 399, 437–439 (1999). https://doi.org/10.1038/20867
Astrophysics and Space Science (2020)
Space Science Reviews (2018)
Environmental Earth Sciences (2018)
Climate Dynamics (2017)