Bibcode
Martinez-Pillet, V.; Klimchuk, James A.; Melrose, Donald B.; Cauzzi, Gianna; van Driel-Gesztelyi, Lidia; Gopalswamy, Natchimuthuk; Kosovichev, Alexander; Mann, Ingrid; Schrijver, Carolus J.
Bibliographical reference
Transactions IAU, Volume 7, Issue T28A, p. 61-68
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4
2012
Citations
0
Refereed citations
0
Description
The solar activity cycle entered a prolonged quiet phase that started in
2008 and ended in 2010. This minimum lasted for a year longer than
expected and all activity proxies, as measured from Earth and from
Space, reached minimum values never observed before (de Toma, 2012). The
number of spotless days from 2006 to 2009 totals 800, the largest ever
recorded in modern times. Solar irradiance was at historic minimums. The
interplanetary magnetic field was measured at values as low as 2.9 nT
and the cosmic rays were observed at records-high. While rumors spread
that the Sun could be entering a grand minimum quiet phase (such as the
Maunder minimum of the XVII century), activity took over in 2010 and we
are now well into Solar Cycle 24 (albeit, probably, a low intensity
cycle), approaching towards a maximum due by mid 2013. In addition to
bringing us the possibility to observe a quiet state of the Sun and of
the Heliosphere that was previously not recorded with modern
instruments, the Sun has also shown us how little we know about the
dynamo mechanism that drives its activity as all solar cycle predictions
failed to see this extended minimum coming.