Rotational effects on the negative magnetic pressure instability

The surface layers of the Sun are strongly stratified. In the presence of turbulence with a weak mean magnetic field, a large-scale instability resulting in the formation of nonuniform magnetic structures, can be excited on the scale of many turbulent eddies. This paper aims to understand the effect...

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Bibliographic Details
Published in:Astronomy and astrophysics (Berlin) 2012-12, Vol.548, p.1-1
Main Authors: Losada, I R, Brandenburg, A, Kleeorin, N, Mitra, D, Rogachevskii, I
Format: Article
Language:English
Subjects:
Fluid dynamics
Helicity
Instability
Nonuniform
Stability
Sun
Three dimensional
Turbulence
Online Access:Get full text
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Summary:The surface layers of the Sun are strongly stratified. In the presence of turbulence with a weak mean magnetic field, a large-scale instability resulting in the formation of nonuniform magnetic structures, can be excited on the scale of many turbulent eddies. This paper aims to understand the effects of rotation on this instability in both two and three dimensions. The authors find that the instability is already suppressed for relatively slow rotation with Coriolis numbers around 0.2. The suppression is strongest at the equator. Hence, the authors speculate that the prograde rotation of the magnetic pattern near the equator might be a possible explanation for the faster rotation speed of magnetic tracers relative to the plasma velocity on the Sun. In the bulk of the domain, kinetic and current helicities are negative in the northern hemisphere and positive in the southern.
ISSN:0004-6361
1432-0746