A Babcock-Leighton-type Solar Dynamo Operating in the Bulk of the Convection Zone

Abstract

The toroidal magnetic field is assumed to be generated in the tachocline in most Babcock-Leighton (BL)-type solar dynamo models, in which the poloidal field is produced by the emergence and subsequent dispersal of sunspot groups. However, magnetic activity of fully convective stars and MHD simulations of global stellar convection have recently raised serious doubts regarding the importance of the tachocline in the generation of the toroidal field. In this study, we aim to develop a new BL-type dynamo model, in which the dynamo operates mainly within the bulk of the convection zone. Our 2D model includes the effect of solar-like differential rotation, one-cell meridional flow, near-surface radial pumping, strong turbulent diffusion, BL-type poloidal source, and nonlinear back-reaction of the magnetic field on its source with a vertical outer boundary condition. The model leads to a simple dipolar configuration of the poloidal field that has the dominant latitudinal component, which is wound up by the latitudinal shear within the bulk of the convection zone to generate the toroidal flux. As a result, the tachocline plays a negligible role in the model. The model reproduces the basic properties of the solar cycle, including (a) approximately 11 yr cycle period and 18 yr extended cycle period; (b) equatorward propagation of the antisymmetric toroidal field starting from high latitudes; and (c) polar field evolution that is consistent with observations. Our model opens the possibility for a paradigm shift in understanding the solar cycle to transition from the classical flux transport dynamo.

arXiv comment17 pages, 10 figures, accepted for publication in ApJ

References in corpus (50)

• The Solar Cycle
• The case for a distributed solar dynamo shaped by near-surface shear
• Detection of Equatorward Meridional Flow and Evidence of Double-Cell Meridional Circulation inside the Sun
• Sunspot group tilt angles and the strength of the solar cycle
• Full--Sphere Simulations of a Circulation--Dominated Solar Dynamo: Exploring the Parity Issue
• The Sun's Global Photospheric and Coronal Magnetic Fields: Observations and Models
• 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
• The crucial role of surface magnetic fields for the solar dynamo
• Magnetic Wreaths and Cycles in Convective Dynamos
• Solar Cycle Propagation, Memory, and Prediction: Insights from a Century of Magnetic Proxies
• Magnetic Flux Transport at the Solar Surface
• A simulation of convective dynamo in the solar convective envelope: maintenance of the solar-like differential rotation and emerging flux
• Solar Meridional Circulation from Doppler Shifts of the Fe I line at lambda 5250 Angstroms as Measured by the 150-foot Solar Tower Telescope at the Mt. Wilson Observatory
• The flare catalog and the flare activity in the Kepler mission
• Global helioseismic evidence for a deeply penetrating Solar meridional flow consisting of multiple flow cells
• Meridional circulation in the solar convection zone: time-distance helioseismic inferences from four years of HMI/SDO observations
• Predictability of the solar cycle over one cycle
• 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
• Deciphering Solar Magnetic Activity I: On The Relationship Between The Sunspot Cycle And The Evolution Of Small Magnetic Features
• 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
• On the role of tachoclines in solar and stellar dynamos
• Buoyant Magnetic Loops Generated by Global Convective Dynamo Action
• Modeling Solar Cycles 15 to 21 Using a Flux Transport Dynamo
• Meridional Flow in the Solar Convection Zone II: Helioseismic Inversions of GONG Data
• Solar parity issue with flux-transport dynamo
• Does the Babcock--Leighton Mechanism Operate on the Sun?
• Magnetic Quenching of Turbulent Diffusivity: Reconciling Mixing-length Theory Estimates with Kinematic Dynamo Models of the Solar Cycle
• A coupled $2\times 2$D Babcock-Leighton solar dynamo model. II. Reference dynamo solutions
• Babcock-Leighton solar dynamo: the role of downward pumping and the equatorward propagation of activity
• Surface flux evolution constraints for flux transport dynamos
• Source of a Prominent Poleward Surge During Solar Cycle 24
• Helioseismic data inclusion in solar dynamo models
• Understanding solar cycle variability
• Convection-driven spherical shell dynamos at varying Prandtl numbers
• 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
• Solar Dynamo Model with Diamagnetic Pumping and Nonlocal Alpha-Effect
• How supercritical are stellar dynamos, or why do old main-sequence dwarfs not obey gyrochronology?
• Sunspot tilt angles revisited: Dependence on the solar cycle strength
• Star-in-a-box simulations of fully convective stars
• An update of Leighton's solar dynamo model
• How does the shape and thickness of the tachocline affect the distribution of the toroidal magnetic fields in the solar dynamo?
• Activity Complexes and A Prominent Poleward Surge During Solar Cycle 24
• Optimization of surface flux transport models for the solar polar magnetic field
• A joined model for solar dynamo and differential rotation
• The relationship between flux emergence and subsurface toroidal magnetic flux

Cited by in corpus (13)

• Physical Models for Solar Cycle Predictions
• Mean field models of flux transport dynamo and meridional circulation in the Sun and stars
• Comparison of physics-based prediction models of solar cycle 25
• Toward a live homogeneous database of solar active regions based on SOHO/MDI and SDO/HMI synoptic magnetograms.II.parameters for solar cycle variability
• The Dependence of Stellar Activity Cycles on Effective Temperature
• Modeling effects of starspots on stellar magnetic cycles
• Minimal Roles of Solar Subsurface Meridional Flow in the distributed-shear Babcock-Leighton Dynamo
• A Potential New Mechanism for the Butterfly Diagram of the Solar Cycle: Latitude-dependent Radial Flux Transport
• Flaring Activities of Fast Rotating Stars have Solar-like Latitudinal Distribution
• Four ages of rotating stars in the rotation--activity relationship and gyrochronology
• A Babcock-Leighton dynamo model of the Sun incorporating toroidal flux loss and the helioseismically-inferred meridional flow
• Constraining the outer boundary condition for the Babcock-Leighton dynamo models
• Can meridional flow variations explain the observed rising/declining phase asymmetry in the solar cycle?