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.

arXiv comment40 pages, 14 figures, 1 table, accepted by The Astrophysical Journal

References in corpus (12)

• Radiative MHD simulation of sunspot structure
• Numerical simulations of quiet Sun magnetism: On the contribution from a small-scale dynamo
• Dynamo Action in the Solar Convection Zone and Tachocline: Pumping and Organization of Toroidal Fields
• Global Seismology of the Sun
• A more realistic representation of overshoot at the base of the solar convective envelope as seen by helioseismology
• High-resolution calculation of the solar global convection with the reduced speed of sound technique: II. Near surface shear layer with the rotation
• On the role of tachoclines in solar and stellar dynamos
• Convective dynamos in spherical wedge geometry
• High-resolution calculations of the solar global convection with the reduced speed of sound technique: I. The structure of the convection and the magnetic field without the rotation
• Efficient small-scale dynamo in solar convection zone
• Numerical Calculation of Convection with Reduced Speed of Sound Technique
• Effects of Penetrative Convection on Solar Dynamo

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