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Detailed Reference Information |
Cliver, E.W., Boriakoff, V. and Bounar, K.H. (1998). Geomagnetic activity and the solar wind during the Maunder Minimum. Geophysical Research Letters 25: doi: 10.1029/98GL00500. issn: 0094-8276. |
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We used a strong (r=0.96) correlation between 11-year averages of sunspot number (SSN) and the geomagnetic aa index to infer that the mean level of geomagnetic activity during the Maunder Minimum (1645-1715) was approximately a third of that observed for recent solar cycles (~7 nT vs. ~24 nT). We determined the variation of 11-year averages of solar wind speed (v) and the southward component of the interplanetary magnetic field (Bs) with cycle-averaged SSN for the two most recent cycles and also compared cycle-averaged variations of v2Bs and aa for the same interval. We then extrapolated these observed solar wind variations to Maunder Minimum conditions (mean SSN of ~2 and mean aa value of ~7 nT) to deduce that, on average, the solar wind during that period was somewhat slower (v=340¿50 km s-1), and the interplanetary magnetic field much smoother (Bs=0.3¿0.1 nT), than at present (~440 km s-1 and ~1.2 nT). Various lines of evidence (including 10Be data) suggest that, despite the virtual absence of sunspots that characterized the Maunder Minimum, the 11-year geomagnetic (solar wind) cycle persisted throughout this period. ¿ 1998 American Geophysical Union |
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BACKGROUND DATA FILES |
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Abstract |
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Keywords
Magnetospheric Physics, Solar wind/magnetosphere interactions, Solar Physics, Astrophysics, and Astronomy, Corona, Solar Physics, Astrophysics, and Astronomy, Solar and stellar variability |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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