Mean field models of flux transport dynamo and meridional circulation in the Sun and stars

Abstract

The most widely accepted model of the solar cycle is the flux transport dynamo model. This model evolved out of the traditional $\alpha \Omega$ dynamo model which was first developed at a time when the existence of the Sun's meridional circulation was not known. In these models, the toroidal magnetic field (which gives rise to sunspots) is generated by the stretching of the poloidal field by solar differential rotation. The primary source of the poloidal field in the flux transport models is attributed to the Babcock--Leighton mechanism, in contrast to the mean-field $\alpha$-effect used in earlier models. With the realization that the Sun has a meridional circulation, which is poleward at the surface and is expected to be equatorward at the bottom of the convection zone, its importance for transporting the magnetic fields in the dynamo process was recognized. Much of our understanding about the physics of both the meridional circulation and the flux transport dynamo has come from the mean field theory obtained by averaging the equations of MHD over turbulent fluctuations. The mean field theory of meridional circulation makes clear how it arises out of an interplay between the centrifugal and thermal wind terms. We provide a broad review of mean field theories for solar magnetic fields and flows, the flux transport dynamo modeling paradigm and highlight some of their applications to solar and stellar magnetic cycles. We also discuss how the dynamo-generated magnetic field acts on the meridional circulation of the Sun and how the fluctuations in the meridional circulation, in turn, affect the solar dynamo. We conclude with some remarks on how the synergy of mean field theories, flux transport dynamo models, and direct numerical simulations can inspire the future of this field.

arXiv comment43 pages, 8 figures, submitted to Space Science Reviews

References in corpus (111)

• Astrophysical magnetic fields and nonlinear dynamo theory
• The Solar Cycle
• The stellar activity-rotation relationship and the evolution of stellar dynamos
• Grand minima and maxima of solar activity: New observational constraints
• Stellar magnetism: empirical trends with age and rotation
• Solar Interior Rotation and its Variation
• Predicting solar cycle 24 with a solar dynamo model
• Detection of Equatorward Meridional Flow and Evidence of Double-Cell Meridional Circulation inside the Sun
• Solar cycle prediction
• Chromospheric activity catalogue of 4454 cool stars. Questioning the active branch of stellar activity cycles
• Sunspot group tilt angles and the strength of the solar cycle
• The effect of magnetic topology on thermally-driven winds: towards a general formulation of the braking law
• Solar activity forecast with a dynamo model
• Full--Sphere Simulations of a Circulation--Dominated Solar Dynamo: Exploring the Parity Issue
• Solar-type dynamo behaviour in fully convective stars without a tachocline
• Exploring the Physical Basis of Solar Cycle Predictions: Flux Transport Dynamics and Persistence of Memory in Advection versus Diffusion Dominated Solar Convection Zones
• Prediction of the strength and timing of sunspot cycle 25 reveal decadal-scale space environmental conditions
• Can we predict the global magnetic topology of a pre-main sequence star from its position in the Hertzsprung-Russell diagram?
• The crucial role of surface magnetic fields for the solar dynamo
• Magnetism, rotation, and nonthermal emission in cool stars -- Average magnetic field measurements in 292 M dwarfs
• Bipolar Magnetic Regions on the Sun: Global Analysis of the SOHO/MDI Data Set
• M-dwarf stellar winds: the effects of realistic magnetic geometry on rotational evolution and planets
• Solar Cycle Propagation, Memory, and Prediction: Insights from a Century of Magnetic Proxies
• Meridional Circulation in Solar and Stellar Convection Zones
• Progress in Solar Cycle Predictions: Sunspot Cycles 24-25 in Perspective
• The unusual minimum of sunspot cycle 23 a consequence of Sun's meridional plasma flow variations
• Origin of the torsional oscillation pattern of solar rotation
• Grand Minima and Equatorward Propagation in a Cycling Stellar Convective Dynamo
• On the role of meridional flows in flux transport dynamo models
• Towards A Mean-Field Formulation Of The Babcock-Leighton Type Solar Dynamo. I. Alpha Coefficient Versus Durney's Double Ring Approach
• Is a deep one-cell meridional circulation essential for the flux transport Solar Dynamo?
• Meridional circulation in the solar convection zone: time-distance helioseismic inferences from four years of HMI/SDO observations
• Parity properties of an advection-dominated solar $α^2\Om$-dynamo
• Magnetoconvection and dynamo coefficients: II. Field-direction dependent pumping of magnetic field
• A Solar Dynamo Model Driven by Mean-Field Alpha and Babcock-Leighton Sources: Fluctuations, Grand-Minima-Maxima and Hemispheric Asymmetry in Sunspot Cycles
• The cause of the weak solar cycle 24
• Importance of Meridional Circulation in Flux Transport Dynamo: The Possibility of a Maunder-like Grand Minimum
• The origin of grand minima in the sunspot cycle
• Differential rotation of main-sequence dwarfs and its dynamo-efficiency
• Reconciling solar and stellar magnetic cycles with nonlinear dynamo simulations
• Multiple dynamo modes as a mechanism for long-term solar activity variations
• Characteristics of solar meridional flows during solar cycle 23
• Turbulent magnetic pumping in a Babcock-Leighton solar dynamo model
• Solar Cycle Variability Induced by Tilt Angle Scatter in a Babcock--Leighton Solar Dynamo Model
• Gyroscopic Pumping in the Solar Near-Surface Shear Layer
• The Hemispheric Asymmetry of Solar Activity During the Twentieth Century and the Solar Dynamo
• Exploring the $P_{cyc}$ vs $P_{rot}$ relation with flux transport dynamo models of solar-like stars
• Planet-induced radio emission from the coronae of M dwarfs: the case of Prox Cen and AU Mic
• A 3D Babcock-Leighton Solar Dynamo Model
• Powering Stellar Magnetism: Energy Transfers in Cyclic Dynamos of Sun-like Stars
• A Double-Ring Algorithm for Modeling Solar Active Regions: Unifying Kinematic Dynamo Models and Surface Flux-Transport Simulations
• Turbulent Pumping of Magnetic Flux Reduces Solar Cycle Memory and thus Impacts Predictability of the Sun's Activity
• Estimating activity cycles with probabilistic methods II. The Mount Wilson Ca H&K data
• Magnetic Quenching of Turbulent Diffusivity: Reconciling Mixing-length Theory Estimates with Kinematic Dynamo Models of the Solar Cycle
• Transition from axi- to nonaxisymmetric dynamo modes in spherical convection models of solar-like stars
• The Waldmeier effect and the flux transport solar dynamo
• Kinematic active region formation in a three-dimensional solar dynamo model
• On the penetration of meridional circulation below the solar convection zone
• Magnetoconvection and dynamo coefficients III: alpha-effect and magnetic pumping in the rapid rotation regime
• Babcock-Leighton solar dynamo: the role of downward pumping and the equatorward propagation of activity
• A Stochastically Forced Time Delay Solar Dynamo Model: Self-Consistent Recovery from a Maunder-like Grand Minimum Necessitates a Mean-Field Alpha Effect
• Surface flux evolution constraints for flux transport dynamos
• Turbulent transport coefficients in spherical wedge dynamo simulations of solar-like stars
• Helioseismic data inclusion in solar dynamo models
• A possible explanation of the Maunder minimum from a flux transport dynamo model
• The mean electro-motive force, current- and cross-helicity under the influence of rotation, magnetic field and shear
• The origin of the solar magnetic cycle
• Dynamo cycles in global convection simulations of solar-like stars
• Changes of the solar meridional velocity profile during cycle 23 explained by flows towards the activity belts
• Kinematic solar dynamo models with a deep meridional flow
• A theoretical study of the build-up of the Sun's polar magnetic field by using a 3D kinematic dynamo model
• Differential rotation of main-sequence dwarfs: predicting the dependence on surface temperature and rotation rate
• The Effects of Magnetic Fields on Observational Signatures of Atmospheric Escape in Exoplanets: Double Tail Structures
• Characterisation of the turbulent electromotive force and its magnetically-mediated quenching in a global EULAG-MHD simulation of solar convection
• A dynamo model of magnetic activity in solar-like stars with different rotational velocities
• Solar Dynamo Model with Diamagnetic Pumping and Nonlocal Alpha-Effect
• The Origin of Parity Changes in the Solar Cycle
• The eddy heat-flux in rotating turbulent convection
• Starspots, Stellar Cycles and Stellar Flares: Lessons from Solar Dynamo Models
• A proposed paradigm for solar cycle dynamics mediated via turbulent pumping of magnetic flux in Babcock-Leighton type solar dynamos
• Correlation between Decay Rate and Amplitude of Solar Cycles as Revealed from Observations and Dynamo Theory
• Why does the Sun's torsional oscillation begin before the sunspot cycle?
• A New Formula for Predicting Solar Cycles
• Quenching of Meridional Circulation in Flux Transport Dynamo Models
• Influence of random fluctuations in the Lambda-effect on meridional flow and differential rotation
• A 3D kinematic Babcock Leighton solar dynamo model sustained by dynamic magnetic buoyancy and flux transport processes
• Modelling variability of solar activity cycles
• Stellar mid-life crisis: subcritical magnetic dynamos of solar-like stars and the breakdown of gyrochronology
• Meridional circulation dynamics from 3D MHD global simulations of solar convection
• A Babcock-Leighton-type Solar Dynamo Operating in the Bulk of the Convection Zone
• Influence of the Sun-like magnetic cycle on exoplanetary atmospheric escape
• Modeling star-planet interactions in far-out planetary and exoplanetary systems
• A theoretical model of the variation of the meridional circulation with the solar cycle
• Exploring cycle period and parity of stellar magnetic activity with dynamo modeling
• Torsional Oscillations in Dynamo Models with Fluctuations and Potential for Helioseismic Predictions of the Solar Cycles
• Dynamo Saturation in Rapidly Rotating Solar-Type Stars
• A joined model for solar dynamo and differential rotation
• Rotational shear near the solar surface as a probe for subphotospheric magnetic fields
• Improved Measurements of the Sun's Meridional Flow and Torsional Oscillation from Correlation tracking on MDI \& HMI magnetograms
• Evidence of persistence of weak magnetic cycles driven by meridional plasma flows during solar grand minima phases
• Incorporating Surface Convection into a 3D Babcock-Leighton Solar Dynamo Model
• Alleviation of catastrophic quenching in solar dynamo model with nonlocal alpha-effect
• On effects of surface bipolar magnetic regions on the convection zone dynamo
• A Theoretical Model of the Near Surface Shear Layer of the Sun
• Suppression of the large-scale Lorentz force by turbulence
• Recent advances in the 3D kinematic Babcock-Leighton solar dynamo modeling
• Three-dimensional non-kinematic simulation of post-emergence evolution of bipolar magnetic regions and Babcock-Leighton dynamo of the Sun
• The Dependence of Stellar Activity Cycles on Effective Temperature
• Mean-field analysis on large-scale magnetic fields at high Reynolds numbers
• A theoretical estimate of the pole-equator temperature difference and a possible origin of the near-surface shear layer
• Dynamical quenching with non-local alpha and downward pumping

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• On the origin of long-term modulation in the Sun's magnetic activity cycle
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