Thermoelectric Properties of Fe0.2Co3.8Sb12-xTex ... - Physics

Why does sun occasionally stop giving sunspots for several years?
Bidya Binay Karak & Arnab Rai Choudhuri
One of the most striking aspects of the 11-year sunspot cycle is that there have been times in the past
when some cycles went missing. A most well-known example of this is the Maunder minimum in 17 th
century when sunspots disappeared for about 70 years. Analyses of cosmogenic isotopes (C14 and
Be10) indicate that there were about 27 grand minima in the last 11,000 yr. This implies that about 2.7
of the solar cycles had conditions appropriate for forcing the Sun into grand minima. We address the
question how grand minima are produced and specifically calculate the frequency of occurrence of
grand minima from a theoretical model. With reasonable assumptions we show that a dynamo model
leads to the conclusion that about 1-4% of the sunspot cycles may have conditions suitable for inducing
grand minima.