What modulates our Sun? The majority of science work on the principle that the Sun is self modulating and each solar cycle is a product of a random number generator. There are others that suspect the Sun is modulated by the planets with a special emphasis on Uranus & Neptune. Thanks to Carl Smith who has recently left us we have new knowledge that significantly adds to Jose, Landscheidt & Charvàtovà's work.

Geoff Sharp

New Paper Challenges the "Solar Floor" Hypothesis and Sheds New Light on the Maunder Minimum.


A paper published in the Astrophysical Journal "Inferring the Structure of the Solar Corona and Inner Heliosphere During the Maunder Minimum Using Global Thermodynamic Magnetohydrodynamic Simulations" by authors Pete Riley, Roberto Lionello, Jon A. Linker, Ed Cliver, Andre Balogh, Jürg Beer, Paul Charbonneau, Nancy Crooker, Marc DeRosa, Mike Lockwood, Matt Owens, Ken McCracken, Ilya Usoskin, and S. Koutchmy

challenges the notion of a "solar floor"  at SC22/23 minimum levels and also discusses the likelihood that the Maunder Minimum was an evolving state of decline very different to the recent SC23/24 minimum. There is some discussion of the polar field influence on the next cycle which I think is floored and this theory will finally be determined after SC25. My thoughts are the magnetic fields of a solar cycle are generated from the tachocline with the pole strength also being an important factor, my views are the pole strength is an after effect of the previous cycle and not subject to random walk type fluctuations.

In the final discussion the paper states we are about to enter the next solar grand minimum inferring perhaps a return to Maunder Minimum like conditions. I believe we are already in a grand minimum state albeit weak, and the chances of a Maunder type minimum are beyond 1000 years away.

The paper can be viewed in full at:

Any comments are most welcome.


Many thanks go to Carl's brother Dave for providing the Domain, Server and Software.