Related papers: Stellar dynamo models with prominent surface toroi…
This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also…
The current understanding of astrophysical magnetic fields is reviewed, focusing on their generation and maintenance by turbulence. In the astrophysical context this generation is usually explained by a self-excited dynamo, which involves…
Observations of chromospheric and coronal emissions from various solar-type stars show that the stellar magnetic activity varies with the rotation rates of the stars. The faster the star rotates, its magnetic activity gets stronger but…
The question of the origin and evolution of magnetic fields in stars possessing a radiative envelope, like the A-type stars, is still regarded as a challenge for stellar physics. Those zones are likely to be differentially rotating, which…
Theoretical models for the solar dynamo range from simple low-dimensional ``toy models'' to complex 3D-MHD simulations. Here we mainly discuss appproaches that are motivated and guided by solar (and stellar) observations. We give a brief…
Massive star winds are important contributors to the energy, momentum and chemical enrichment of the interstellar medium. Strong, organized and predominantly dipolar magnetic fields have been firmly detected in a small subset of massive…
I review the development of ideas regarding the angular momentum evolution of solar-type stars, from the early 60's to the most recent years. Magnetic fields are the central agent that dictates the rotational evolution of solar-type stars,…
The theory of planetary dynamos and its applications to observed phenomena of planetary magnetism are outlined. It is generally accepted that convection flows driven by thermal or compositional buoyancy are the most likely source for the…
We investigate the chiral magnetic instability in the crust of a neutron star as a potential mechanism for amplifying magnetic fields. This instability may become active when small deviations from chemical equilibrium are sustained over…
The geo and solar magnetic fields have long been thought to be very different objects both in terms of spatial structure and temporal behavior. The recently discovered field structure of a fully convective star is more reminiscent of…
Stellar magnetic fields are produced by a magnetohydrodynamic dynamo mechanism working in their interior -- which relies on the interaction between plasma flows and magnetic fields. The Sun, being a well-observed star, offers an unique…
The variable magnetic field of the solar photosphere exhibits periodic reversals as a result of dynamo activity occurring within the solar interior. We decompose the surface field as observed by both the Wilcox Solar Observatory and the…
Recent asteroseismic analyses have revealed the presence of strong (B $\gtrsim 10^5$ G) magnetic fields in the cores of many red giant stars. Here, we examine the implications of these results for the evolution of stellar magnetic fields,…
A key question in understanding the observed magnetic field topologies of cool stars is the link between the small- and the large-scale magnetic field and the influence of the stellar parameters on the magnetic field topology. We examine…
Increasing evidence is becoming available about not only the surface differential rotation of rapidly rotating cool stars but, in a small number of cases, also about temporal variations, which possibly are analogous to the solar torsional…
Early-type stars show a bimodal distribution of magnetic field strengths, with some showing very strong fields ($\gtrsim 1\,\mathrm{kG}$) and others very weak fields ($\lesssim 10\,\mathrm{G}$). Recently, we proposed that this reflects the…
Our theoretical and numerical analysis have suggested that for low-mass main sequences stars (of the spectral classes from M5 to G0) rotating much faster than the Sun, the generated large-scale magnetic field is caused by the mean-field…
A variety of magnetohydrodynamic mechanisms that may play a role in magnetic, chemically peculiar (mCP) stars is reviewed. These involve dynamo mechanisms in laminar flows as well as turbulent environments, and magnetic instabilities of…
Observations with the Hinode spectro-polarimeter have revealed strong horizontal internetwork magnetic fields in the quiet solar photosphere. We aim at interpreting the observations by means of results from numerical simulations. Radiative…
The growing sample of magnetic stars shows a remarkable diversity in the properties of their magnetic fields. The overall goal of current studies is to understand the origin, evolution, and structure of stellar magnetic fields in stars of…