A simple way to couple an interface dynamo model to a fast tachocline model is presented, under the assumption that the dynamo saturation is due to a quadratic process and that the effect of finite shear layer thickness on the dynamo wave frequency is analoguous to the effect of finite water depth on surface gravity waves. The model contains one free parameter which is fixed by the requirement ...

The character of solar rotation has been examined for two periods in the early 17th century for which detailed sunspot drawings are available: A.D. 1625 through 1626 and 1642 through 1644. The first period occurred 20 years before the start of the Maunder sunspot minimum, 1645 through 1715; the second occurred just at its commencement. Solar rotation in the earlier period was much like that of ...

There exists a considerable amount of research claiming a puzzling anti-correlation between the neutrino detection rate at the Homestake experiment and indicators of solar activity such as the sunspot number, giving rise to explanations involving the hypothesis of a neutrino magnetic moment. It is argued here that the claimed significant anti-correlation is due to a statistical fallacy. A prope...

Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview of the special indices used to quantify different aspects of variable solar activity, with special emphasis upon sunspot

Model predictions of the distribution and dynamical transport of hydrogen atoms in the terrestrial atmosphere have long-standing discrepancies with ultraviolet remote sensing measurements, indicating likely deficiencies in conventional theories regarding this crucial atmospheric constituent. Here we report the existence of non-thermal hydrogen atoms that are much hotter than the ambient oxygen ...

We define the solar cycle as a spatiotemporal rather than a purely temporal entity. This allows us to introduce new methods to determine timing parameters of the activity cycles. We discuss the physical interpretation of our spatiotemporal definition as a pair of activity waves travelling towards the equator and pole respectively, and present results of the corresponding statistical analysis. T...

Measurements of the Sun semidiameter made with the Danjon astrolabe at Santiago, Chile, and with the magnetograph of the solar telescope of Mount Wilson Observatory during the period 1990-1995, show similar variations in time and with a similar trend as the variation of sunspot number. The consistency of these results obtained at different sites and with rather different observing techniques co...