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Double-diffusive Magnetic Layering

delete2021-11-30
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OA
AI
D
David W. Hughes *
N
Nicholas H. Brummell
DOI:10.3847/1538-4357/ac2057delete
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Abstract

Abstract

En 中文
Double-diffusive systems, such as thermosolutal convection, in which the density depends on two components that diffuse at different rates, are prone to both steady and oscillatory instabilities. Such systems can evolve into layered states, in which both components, and also the density, adopt a staircase profile. Turbulent transport is enhanced significantly in the layered state. Here we exploit an analogy between magnetic buoyancy and thermosolutal convection in order to demonstrate the phenomenon of magnetic layering. We examine the long-term nonlinear evolution of a vertically stratified horizontal magnetic field in the so-called diffusive regime, where an oscillatory linear instability operates. Motivated astrophysically, we consider the case where the viscous and magnetic diffusivities are much smaller than the thermal diffusivity. We demonstrate that diffusive layering can occur even for subadiabatic temperature gradients. Magnetic layering may be relevant for stellar radiative zones, with implications for the turbulent transport of heat, magnetic field, and chemical elements.
Keywords:
BOUSSINESQ APPROXIMATION
CONVECTIVE INSTABILITY
ADIABATIC STABILITY
STARS
BUOYANCY
FIELDS
TRANSPORT
FLUID

Journal

Astrophysical Journal cover
Astrophysical Journal
IF:
5.4
Papers:
8.3W
Citations:
32.0W

Organization

University of California System cover
University of California System
Scholars:
37.5W
Papers: 33.7W
Citations: 6.6K
U
university of leeds
Scholars:
3.6W
Papers: 3.3W
Citations: 45