Magnetically Modulated Heat Transport in a Global Simulation of Solar Magneto-convection

We present results from a global MHD simulation of solar convection in which the heat transported by convective flows varies in-phase with the total magnetic energy. The purely random initial magnetic field specified in this experiment develops into a well-organized large-scale antisymmetric compone...

Full description

Saved in:
Bibliographic Details
Published in:The Astrophysical journal 2017-05, Vol.841 (1), p.65
Main Authors: Cossette, Jean-Francois, Charbonneau, Paul, Smolarkiewicz, Piotr K., Rast, Mark P.
Format: Article
Language:English
Subjects:
Astrophysics
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
CONVECTION
Convection cooling
Convection heating
Convective flow
Cooling
dynamo
ENTROPY
EQUATIONS
HEAT FLUX
Heat transfer
Heat transport
Heating and cooling
Irradiance
MAGNETIC FIELDS
MAGNETOHYDRODYNAMICS
magnetohydrodynamics (MHD)
MODULATION
Polarity
RADIANT FLUX DENSITY
RANDOMNESS
SIMULATION
Solar convection
Solar convection (astronomy)
Solar irradiance
SPECIFICATIONS
STRATIFICATION
SUN
Sun: activity
Sun: interior
Thermal cycling
Transport
TURBULENCE
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present results from a global MHD simulation of solar convection in which the heat transported by convective flows varies in-phase with the total magnetic energy. The purely random initial magnetic field specified in this experiment develops into a well-organized large-scale antisymmetric component undergoing hemispherically synchronized polarity reversals on a 40 year period. A key feature of the simulation is the use of a Newtonian cooling term in the entropy equation to maintain a convectively unstable stratification and drive convection, as opposed to the specification of heating and cooling terms at the bottom and top boundaries. When taken together, the solar-like magnetic cycle and the convective heat flux signature suggest that a cyclic modulation of the large-scale heat-carrying convective flows could be operating inside the real Sun. We carry out an analysis of the entropy and momentum equations to uncover the physical mechanism responsible for the enhanced heat transport. The analysis suggests that the modulation is caused by a magnetic tension imbalance inside upflows and downflows, which perturbs their respective contributions to heat transport in such a way as to enhance the total convective heat flux at cycle maximum. Potential consequences of the heat transport modulation for solar irradiance variability are briefly discussed.
ISSN:0004-637X
1538-4357
DOI:10.3847/1538-4357/aa6d60