On the dynamical interaction between overshooting convection and an underlying dipole magnetic field – I. The non-dynamo regime

Author:

Korre L1,Brummell NH2,Garaud P2,Guervilly C3

Affiliation:

1. Laboratory for Atmospheric and Space Physics, Boulder, CO 80303, USA

2. Department of Applied Mathematics, Jack Baskin School of Engineering, University of California Santa Cruz, Santa Cruz, CA 95064, USA

3. School of Mathematics, Statistics and Physics, Newcastle University, Newcastle upon Tyne NE17RU, UK

Abstract

ABSTRACT Motivated by the dynamics in the deep interiors of many stars, we study the interaction between overshooting convection and the large-scale poloidal fields residing in radiative zones. We have run a suite of 3D Boussinesq numerical calculations in a spherical shell that consists of a convection zone with an underlying stable region that initially compactly contains a dipole field. By varying the strength of the convective driving, we find that, in the less turbulent regime, convection acts as turbulent diffusion that removes the field faster than solely molecular diffusion would do. However, in the more turbulent regime, turbulent pumping becomes more efficient and partially counteracts turbulent diffusion, leading to a local accumulation of the field below the overshoot region. These simulations suggest that dipole fields might be confined in underlying stable regions by highly turbulent convective motions at stellar parameters. The confinement is of large-scale field in an average sense and we show that it is reasonably modelled by mean-field ideas. Our findings are particularly interesting for certain models of the Sun, which require a large-scale, poloidal magnetic field to be confined in the solar radiative zone in order to explain simultaneously the uniform rotation of the latter and the thinness of the solar tachocline.

Funder

National Aeronautics and Space Administration

Natural Environment Research Council

NASA

National Science Foundation

Publisher

Oxford University Press (OUP)

Subject

Space and Planetary Science,Astronomy and Astrophysics

Cited by 6 articles. 订阅此论文施引文献 订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献

1. Dynamics of the Tachocline;Space Science Reviews;2023-12

2. An Atlas of Convection in Main-sequence Stars;The Astrophysical Journal Supplement Series;2022-08-24

3. The Rise of Buoyant Magnetic Structures through Convection with a Background Magnetic Field;The Astrophysical Journal;2022-04-01

4. Local heating due to convective overshooting and the solar modelling problem;Astronomy & Astrophysics;2021-12-31

5. Magnetic Archaeology of Early-type Stellar Dynamos;The Astrophysical Journal;2021-12-01

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