Related papers: Flux transport solar dynamo models, current proble…
Recent results indicate that the Babcock-Leighton mechanism for poloidal field creation plays an important role in the solar cycle. However, modelling this mechanism has not always correctly captured the underlying physics. In particular,…
We discuss the difficulties of predicting the solar cycle using mean-field models. Here we argue that these difficulties arise owing to the significant modulation of the solar activity cycle, and that this modulation arises owing to either…
The Sun shows a wide range of temporal variations, from a few seconds to decades and even centuries, broadly classified into two classes short-term and Long-term. The solar dynamo mechanism is believed to be responsible for these global…
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…
Helioseismology shows that the regions occupied by convection and differential rotation inside the sun almost coincide. This supports the leading theoretical concept for the origin of differential rotation as a result of interaction between…
Meridional circulation is an important ingredient in flux transport dynamo models. We have studied its importance on the period, the amplitude of the solar cycle, and also in producing Maunder-like grand minima in these models. First, we…
We present a 3D kinematic solar dynamo model in which poloidal field is generated by the emergence and dispersal of tilted sunspot pairs (more generally Bipolar Magnetic Regions, or BMRs). The axisymmetric component of this model functions…
Detailed study of the solar magnetic field is crucial to understand its generation, transport and reversals. The timing of the reversals may have implications on space weather and thus identification of the temporal behavior of the critical…
The subsurface meridional flow has long been recognized as a critical factor in driving the solar cycle. Specifically, the equatorward return flow in the tachocline is widely believed to be responsible for the formation of the sunspot…
The Sun's global meridional circulation is evident as a slow poleward flow at its surface. This flow is observed to carry magnetic elements poleward - producing the Sun's polar magnetic fields as a key part of the 11-year sunspot cycle.…
The prediction of the strength of future solar cycles is of interest because of its practical significance for space weather and as a test of our theoretical understanding of the solar cycle. The Babcock-Leighton mechanism allows…
The butterfly diagram of the solar cycle is the equatorward migration of the emergence latitudes of sunspots as the solar cycle evolves. Revealing the mechanism for the butterfly diagram is essential for understanding the solar and stellar…
We model the surface magnetic field and open flux of the Sun from 1913 to 1986 using a surface flux transport model, which includes the observed cycle-to-cycle variation of sunspot group tilts. The model reproduces the empirically derived…
Observations of the solar magnetic cycle showed that the amplitude of the cycle did not grow all the time in the past. Thus, there must be a mechanism to halt the growth of the magnetic field in the Sun. We demonstrate a recently proposed…
The polar magnetic field of the Sun is a manifestation of certain aspects of the dynamo process and is a good precursor for predicting a sunspot cycle before its onset. Although actual synoptic measurements of this field exist only from the…
It is well accepted that the solar cycle originates from a magnetohydrodynamics dynamo deep inside the Sun. Many dynamo models have long been proposed based on a lot of observational constraints. In this paper, using 342 NSO/Kitt Peak solar…
Solar magnetic fields comprise an 11-year activity cycle, represented by the number of sunspots. The maintenance of such a solar magnetic field can be attributed to fluid motion in the convection zone, i.e. a dynamo. This study conducts the…
Dynamo models relying on the Babcock-Leighton mechanism are successful in reproducing most of the solar magnetic field dynamical characteristics. However, considering that such models operate only above a lower magnetic field threshold,…
Three closely related stumbling blocks of solar mean field dynamo theory are discussed: how dominant are the small scale fields, how is the alpha effect quenched, and whether magnetic and current helicity fluxes alleviate the quenching? It…
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…