Mean-field dynamo theory has important applications in solar physics and galactic
magnetism. We discuss some of the many turbulence effects relevant to the generation of …

A brief summary of the various observations and constraints that underlie solar dynamo
research are presented. The arguments that indicate that the solar dynamo is an alpha …

We live in an age in which high-performance computing is transforming the way we do
science. Previously intractable problems are now becoming accessible by means of …

Turbulence and the associated turbulent transport of scalar and vector fields is a classical
physics problem that has dazzled scientists for over a century, yet many fundamental …

Recent studies have demonstrated that in fully developed turbulence, the effective magnetic
pressure of a large-scale field (non-turbulent plus turbulent contributions) can become …

ABSTRACT A theory of the mean tilt of sunspot bipolar regions (the angle between a line
connecting the leading and following sunspots and the solar equator) is developed. A …

Context. Observations from the Solar Dynamics Observatory (SDO) have the potential for
allowing the helioseismic study of the formation of hundreds of active regions, which would …

In the presence of strong density stratification, hydromagnetic turbulence attains qualitatively
new properties: the formation of magnetic flux concentrations. We review here the theoretical …

We investigate the dynamics of solar activity using a nonlinear one-dimensional dynamo
model and a phenomenological equation for the evolution of Wolf numbers. This system of …

Context. The formation of magnetic flux concentrations within the solar convection zone
leading to sunspot formation is unexplained. Aims. We study the self-organization of initially …