Related papers: Is there a phase constraint for solar dynamo model…
The dynamic activity of stars such as the Sun influences (exo)planetary space environments through modulation of stellar radiation, plasma wind, particle and magnetic fluxes. Energetic stellar phenomena such as flares and coronal mass…
Sunspots are regions of decreased brightness on the visible surface of the Sun (photosphere) that are associated with strong magnetic fields. They have been found to be locations associated with solar flares, which occur when energy stored…
The evolution of the solar activity comprises, apart from the well-known 11-year cycle, various temporal scales ranging from months up to the secondary cycles known as mid-term oscillations. Its nature deserves a physical explanation. In…
The first results of the solar dynamo model that allows for the diamagnetic effect of inhomogeneous turbulence and the nonlocal alpha-effect due to the rise of magnetic loops are discussed. The nonlocal alpha-effect is not subject to the…
Arguments for and against the widely accepted picture of a solar dynamo being seated in the tachocline are reviewed and alternative ideas concerning dynamos operating in the bulk of the convection zone, or perhaps even in the near-surface…
Spectropolarimetric observations show that many low-mass stars possess large-scale poloidal magnetic fields with considerable dipole component, which in some cases exhibit temporal dynamics - cycles or reversals. Although it is widely…
Using a nonlinear mean-field solar dynamo model, we study relationships between the amplitude of the `extended' mode of migrating zonal flows (`torsional oscillations') and magnetic cycles, and investigate whether properties the torsional…
Context: Observations indicate that the `quiet' solar photosphere outside active regions contains considerable amounts of magnetic energy and magnetic flux, with mixed polarity on small scales. The origin of this flux is unclear. Aims: We…
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-omega dynamo of the Babcock-Leighton type are then shortly…
Many stars exhibit strong magnetic fields, some of which are thought to be of primordial origin and others a sign of magnetic dynamo processes. We briefly review the results of observational studies of solar-type stars seeking to evaluate…
Magnetic field generation in the Sun and solar-type stars is modeled here based on the formation of magnetically polarized condensates (B. M. Mirza, Mod. Phys. Lett. B 28 (2014) 1450148) under the high density and pressure conditions. The…
Simple models of magnetic field generation by convection in rotating spherical shells exhibit properties resembling those observed on the sun. The {assumption of the Boussinesq approximation made in these models} prevents a realistic…
Flux-dominated solar dynamo models, which have demonstrated to be quite successful in reproducing most of the observed features of the large scale solar magnetic cycle, generally produce an inappropriate latitudinal distribution of the…
We show that if the turbulent magnetic diffusivity used in solar dynamos is assumed to be 'quenched' by increasing toroidal fields, much larger amplitude and more concentrated toroidal fields can be induced by differential rotation from an…
We live near a magnetic star whose cycles of activity are driven by dynamo action beneath the surface. In the solar convection zone, rotation couples with plasma motions to build highly organized magnetic fields that erupt at the surface…
The interplanetary magnetic field near has a characteristic "sector" structure that reflects its polarity relative to the solar direction. Typically we observe large-scale coherence in these directions, with two or four "away" or "towards"…
Using even-order frequency splitting coefficients of global p-modes it is possible to infer the magnetic field in the solar interior as a function of radial distance and latitude. Results obtained using GONG and MDI data are discussed.…
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…
Observations of the meridional circulation of the Sun, which plays a key role in the operation of the solar dynamo, indicate that its speed varies with the solar cycle, becoming faster during the solar minima and slower during the solar…
We present axisymmetric numerical simulations of the solar interior, including the convection zone and an extended radiative interior. We find that differential rotation in the convection zone induces a toroidal field from an initially…