Recent progress in astrophysical hydromagnetic turbulence is being reviewed. The physical
ideas behind the now widely accepted Goldreich–Sridhar model and its extension to …

Over the past several decades, Flux-Transport Dynamo (FTD) models have emerged as a
popular paradigm for explaining the cyclic nature of solar magnetic activity. Their defining …

The Pencil Code is a highly modular physics-oriented simulation code that can be adapted
to a wide range of applications. It is primarily designed to solve partial differential equations …

Recent advances in mean-field theory are reviewed and applications to the Sun, late-type
stars, accretion disks, galaxies and the early Universe are discussed. We focus particularly …

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 …

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 …

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 …