Solar overshoot region and small-scale dynamo with realistic energy flux

Abstract

We carry out high resolution calculations of the solar overshoot region with unprecedentedly realistic parameters, especially the small energy flux compared with $\rho c_{\mathrm{s}}^3$, where $\rho$ and $c_{\mathrm{s}}$ are density and speed of sound. Our main purpose is to investigate behavior of the overshoot and the small-scale dynamo with parameters as close as possible to those of the Sun. Our calculations show that the bottom part of the convection zone becomes subadiabatic, which efficiently suppresses downflows. As a result we see a steep transition from the CZ to the RZ whose width is estimated 0.4% of the local pressure scale height. This result is consistent with a semi-analytic convection/overshoot model. We also find that the small-scale dynamo becomes efficient with a smaller energy flux. The sudden suppression of the downflows around the base of the convection zone increases the efficiency of the small-scale dynamo.

40 pages, 14 figures, 1 table, accepted by The Astrophysical Journal

References in corpus (4)

• Numerical simulations of quiet Sun magnetism: On the contribution from a small-scale dynamo
• Global Seismology of the Sun
• High-resolution calculation of the solar global convection with the reduced speed of sound technique: II. Near surface shear layer with the rotation
• Efficient small-scale dynamo in solar convection zone

Cited by in corpus (27)

• Solar inertial modes: Observations, identification, and diagnostic promise
• Magnetic signatures on mixed-mode frequencies. I. An axisymmetric fossil field inside the core of red giants
• Generation solar-like differential rotation
• Stellar convective penetration: parameterized theory and dynamical simulations
• Theory of solar oscillations in the inertial frequency range: Linear modes of the convection zone
• Convective boundary mixing in main-sequence stars: theory and empirical constraints
• A study of convective core overshooting as a function of stellar mass based on two-dimensional hydrodynamical simulations
• Convective velocity suppression via the enhancement of subadiabatic layer: Role of the effective Prandtl number
• Two-dimensional simulations of solar-like models with artificially enhanced luminosity -- I. Impact on convective penetration
• 3D hydrodynamics simulations of internal gravity waves in red giant branch stars
• Two-dimensional simulations of solar-like models with artificially enhanced luminosity. II. Impact on internal gravity waves
• On the dynamics of overshooting convection in spherical shells: Effect of density stratification and rotation
• A finite-volume scheme for modeling compressible magnetohydrodynamic flows at low Mach numbers in stellar interiors
• Prandtl number dependence of compressible convection: Flow statistics and convective energy transport
• Turbulent dynamo action and its effects on the mixing at the convective boundary of an idealized oxygen-burning shell
• Three-dimensional non-kinematic simulation of post-emergence evolution of bipolar magnetic regions and Babcock-Leighton dynamo of the Sun
• Local heating due to convective overshooting and the solar modelling problem
• Upward Overshooting in Turbulent Compressible Convection. III. Calibrate Parameters for One-dimensional Reynolds Stress Model
• Simulations of entropy rain-driven convection
• Penetrative magneto-convection of a rotating Boussinesq flow in $f$-planes
• Global Turbulent Solar Convection: a Numerical Path Investigating Key Force Balances in the context of the Convective Conundrum
• A Babcock-Leighton dynamo model of the Sun incorporating toroidal flux loss and the helioseismically-inferred meridional flow
• Small-scale and large-scale dynamos in global convection simulations of solar-like stars
• Mixing by Internal Gravity Waves in Stars: Assessing Numerical Simulations Against Theory
• Spatial inhomogeneity of kinetic and magnetic dissipations in thermal convection
• Spontaneous Generated Convective Anticyclones in Low Latitude -- A Model for the Great Red Spot
• Effects of the radiative interior on solar inertial modes