The Rise of Active Region Flux Tubes in the Turbulent Solar Convective Envelope

Abstract

We use a thin flux tube model in a rotating spherical shell of turbulent convective flows to study how active region scale flux tubes rise buoyantly from the bottom of the convection zone to near the solar surface. We investigate toroidal flux tubes at the base of the convection zone with field strengths ranging from 15 kG to 100 kG at initial latitudes ranging from 1 degree to 40 degrees with a total flux of 10^22 Mx. We find that the dynamic evolution of the flux tube changes from convection dominated to magnetic buoyancy dominated as the initial field strength increases from 15 kG to 100 kG. At 100 kG, the development of Omega-shaped rising loops is mainly controlled by the growth of the magnetic buoyancy instability. However, at low field strengths of 15 kG, the development of rising Omega-shaped loops is largely controlled by convective flows, and properties of the emerging loops are significantly changed compared to previous results in the absence of convection. With convection, rise times are drastically reduced (from years to a few months), loops are able to emerge at low latitudes, and tilt angles of emerging loops are consistent with Joy's Law for initial field strengths of greater than or equal to 40 kG. We also examine other asymmetries that develop between the leading and following legs of the emerging loops. Taking all the results together, we find that mid-range field strengths of approximately 40 - 50 kG produce emerging loops that best match the observed properties of solar active regions.

Accepted for publication in The Astrophysical Journal

References in corpus (4)

• Sunspot group tilt angles and the strength of the solar cycle
• Structure and Evolution of Giant Cells in Global Models of Solar Convection
• Flux-transport dynamos with Lorentz force feedback on differential rotation and meridional flow: Saturation mechanism and torsional oscillations
• Three dimensional non-linear evolution of a magnetic flux tube in a spherical shell: Influence of turbulent convection and associated mean flows

Cited by in corpus (64)

• Flare-productive active regions
• Magnetic Wreaths and Cycles in Convective Dynamos
• Magnetic Flux Transport at the Solar Surface
• Effects of the scatter in sunspot group tilt angles on the large-scale magnetic field at the solar surface
• Numerical simulations of active region scale flux emergence: From spot formation to decay
• Predictability of the solar cycle over one cycle
• Buoyant Magnetic Loops Generated by Global Convective Dynamo Action
• Helioseismic Imaging of Fast Convective Flows Throughout the Near-Surface Shear Layer
• Emergence of magnetic flux generated in a solar convective dynamo. I: Formation of Sunspots and Active regions, and Origin of Their Asymmetries
• The Solar-Stellar Connection
• Rieger-type periodicity during solar cycles 14-24: estimation of dynamo magnetic field strength in the solar interior
• Lifetimes and Emergence/Decay Rates of Star Spots on Solar-type Stars Estimated by Kepler Data in Comparison with Those of Sunspots
• Comparing Simulations of Rising Flux Tubes Through the Solar Convection Zone with Observations of Solar Active Regions: Constraining the Dynamo Field Strength
• Long-Term Measurements of Sunspot Magnetic Tilt Angles
• Emergence of granular-sized magnetic bubbles through the solar atmosphere: I. Spectropolarimetric observations and simulations
• MHD and deep mixing in evolved stars. 1. 2D and 3D analytical models for the AGB
• On the Amplitude of Convective Velocities in the Deep Solar Interior
• A coupled $2\times 2$D Babcock-Leighton solar dynamo model. II. Reference dynamo solutions
• Kinematic active region formation in a three-dimensional solar dynamo model
• Efficient small-scale dynamo in solar convection zone
• Global Dynamics of Subsurface Solar Active Regions
• Evolution of solar and stellar dynamo theory
• Magnetic field dependence of bipolar magnetic region tilts on the Sun: Indication of tilt quenching
• Physical Models for Solar Cycle Predictions
• A Three-Dimensional Babcock-Leighton Solar Dynamo Model: Initial Results with Axisymmetric Flows
• A theoretical study of the build-up of the Sun's polar magnetic field by using a 3D kinematic dynamo model
• On rising magnetic flux tube and formation of sunspots in a deep domain
• A dynamo model of magnetic activity in solar-like stars with different rotational velocities
• Quenching and anisotropy of hydromagnetic turbulent transport
• Common dynamo scaling in slowly rotating young and evolved stars
• A Systematic Study of Hale and Anti-Hale Sunspot Physical Parameters
• Theoretical limits on magnetic field strengths in low-mass stars
• Average motion of emerging solar active region polarities II: Joy's law
• Flux emergence in a magnetized convection zone
• The Minimum of Solar Cycle 23: As Deep as It Could Be?
• Multi-Parametric Study of Rising 3D Buoyant Flux Tubes in an Adiabatic Stratification Using AMR
• Average motion of emerging solar active region polarities I: Two phases of emergence
• No More Active Galactic Nuclei in Clumpy Disks Than in Smooth Galaxies at z~2 in CANDELS / 3D-HST
• A Theory on the Convective Origins of Active Longitudes on Solar-like Stars
• Modeling the Rise of Fibril Magnetic Fields in Fully Convective Stars
• Analysis of BMR tilt from AutoTAB catalog: Hinting towards the thin flux tube model?
• Dynamo Saturation in Rapidly Rotating Solar-Type Stars
• Effect of morphological asymmetry between leading and following sunspots on the prediction of solar cycle activity
• Is hemispheric asymmetry in the sunspot cycle solely governed by polar flux imbalance in the previous cycle?
• Effects of Radiative Diffusion on Thin Flux Tubes in Turbulent Solar-like Convection
• Magnetic field intensification by three-dimensional explosion process
• Generation of twist on magnetic flux tubes at the base of the solar convection zone
• Flux-tubes forming instability near the base of the rotating convection zone: A possible explanation for low latitudes of sunspots
• Successful and Failed Flux Tube Emergence in the Solar Interior
• Three-dimensional non-kinematic simulation of post-emergence evolution of bipolar magnetic regions and Babcock-Leighton dynamo of the Sun
• Recent advances in the 3D kinematic Babcock-Leighton solar dynamo modeling
• Photospheric Velocity Structures during the Emergence of Small Active Regions on the Sun
• Low-latitude magnetic flux emergence on rapidly rotating solar-type stars
• 3D simulations of rising magnetic flux tubes in a compressible rotating interior: The effect of magnetic tension
• Coriolis force acting on near-surface horizontal flows during simulations of flux emergence produces a tilt angle consistent with Joy's law on the Sun
• Delayed Babcock-Leighton dynamos in the diffusion-dominated regime
• Theoretical and Observational Evidence for Coriolis Effects in Coronal Magnetic Fields Via Direct Current Driven Flaring Events
• Large-Scale Magnetic Field Fragmentation in Flux-Tubes Near the Base of the Solar Convection Zone
• Observed Joys law of Bipolar Magnetic Region tilts at the emergence supports the thin flux tube model
• Evolution of the magnetic field and flows of solar active regions with persistent magnetic bipoles before emergence
• Recovery of the Solar Cycle from Maunder-like Grand Minima Episodes: A Quantification of the Necessary Polar Flux Threshold through Solar Dynamo Simulations
• Modeling the Parker instability in a rotating plasma screw pinch
• The Evolving Magnetic Scales of the Outer Solar Atmosphere and Their Potential Impact on Heliospheric Turbulence
• Examining the Magnetic Field Strength and the Horizontal and Vertical Motions in an Emerging Active Region