Toroidal convection rolls in the sun a challenge to theory

Ribes, E.; Laclare, F.

doi:10.1080/03091928808208849

Cited by 19 publications

(11 citation statements)

References 20 publications

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“…Indirect evidence for the existence of a privileged correlation length can also be found in Roudier & Muller's (1986) work. By measuring the fractal dimension of the granular structures they revealed a change in dimension near the expected granular size.…”

Section: Granulesmentioning

confidence: 85%

“…Numerical as well as experimental work in fact support this conjecture (Hart et al 1986, Gilman & Miller 1986), but they have never been observed. The observation of the so-called torsional oscillations has challenged this confidence (Snodgrass 1987, Snodgrass & Wilson 1987 much as the migrations of young sunspots (Ribes & Mein 1985, Ribes & Laclare 1988. The former authors describe the whole pattern of use, available at https://www.cambridge.org/core/terms.…”

Section: Giant Cellsmentioning

confidence: 99%

“…Muller & Roudier's (1985, Roudier & Muller 1986) observations show a continuum of sizes for the bright regions, with their transversal dimensions decreasing towards values much smaller than those presumed for granules. The power spectrum measured by the above mentioned authors clearly displays an inertial range, with a slope of -5 / 3 as corresponds to the famous KolmogorovObukhov law -see Zahn's (1987) review.…”

Section: Granulesmentioning

confidence: 99%

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Convection in the Sun

Massaguer

1990

International Astronomical Union Colloquium

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ABSTRACT. The present knowledge of the dynamics and structure of the solar convection zone is reviewed with the aim of checking current assumptions and conjectures against laboratory experiments and numerical modeling of thermal convection. Buoyancy is the only forcing considered. Rotation and magnetic fields are explicitly avoided. Nor are departures from planar geometry considered , except as regards large scale structures. Local theories are reviewed in section §2, hydrodynamic models in §3, non-local theories in §4, the global structure of the convection zone is discussed in §5 and the flow patterns in §6. I n t r o d u c t i o nT h e solar convection zone is the site of very rich dynamics, t h e intricacies of which make it difficult to look through it into the deeper interior. Therefore, solar convection theory has often been approached with t h e avowed aim of obtaining a recipe for computing gradients and fluxes in places where a radiative gradient would be unstable. We shall take this view in the first p a r t of the present review. Yet t h e solar convection zone is still t h e site of a highly structured magnetohydrodynamic flow, where buoyancy is thought to be one of the dominant external forcings. This view will be taken later on and buoyancy induced solar structures will also be reviewed.T h e purpose of the present paper is to examine the solar convection zone as a whole, with laboratory a n d numerical experiments in m i n d . We shall a t t e m p t to stress similarities as much as possible and, as a consequence, we shall avoid discussing any process dominated by forcings other t h a n buoyancy. Rotation and magnetic fields will not be considered at all, a n d t h e geometry will be assumed to be planar unless stated otherwise. However, as most of the laboratory experiments and numerical simulations in t h e r m a l convection are extremely dependent on details irrelevant to a stellar interior -the shape of the container, the boundary conditions, etc.-any extrapolation of numerical results or laboratory measurements is to be looked at carefully. O n local t h e o r i e s o f stellar c o n v e c t i o n .Local theories are widely used for modeling t h e r m a l convection in stars, as they are the simplest available algorithms, though some a t t e m p t s at modeling stellar convection zones with non-local theories exist a n d will b e reviewed in §3 and §4. Mixing-length scaling is widely accepted and consistency with it is required for any model, no m a t t e r whether it is local or non-local. However, local models can be derived without any reference to phenomenology. We shall take this view because 101 G. Berthomieu and M. Cribier (eds.), Inside the Sun, 101-115.

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Section: Granulesmentioning

confidence: 85%

Section: Giant Cellsmentioning

confidence: 99%

Section: Granulesmentioning

confidence: 99%

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Convection in the Sun

Massaguer

1990

International Astronomical Union Colloquium

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“…On the one hand, though sunspots and bright faculae may easily explain the short-term fluctuations present in the total solar irradiance, there must be some phenomenon to account for the 11-yr trend (Willson & Hudson 1991). On the other hand, the good anticorrelation between apparent diameter and solar constant data suggests that the azimuthal roll pattern might be the cause of the trend present in both apparent diameter and solar constant data (Ribes & Laclare 1988). The modulation of the surface rotation can be used as a tracer of the thermal response caused by periodic emergence of magnetic fields.…”

Section: The 11-year Solar Cycle: Present Knowledgementioning

confidence: 99%

On a Plausible Physical Mechanism Linking the Maunder Minimum to the Little Ice Age

Nesme-Ribes

Mangeney

1992

Radiocarbon

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“…We note that there have been many attempts to identify much larger structures like "giant cells" but their existence is still questionable. Recently an interpretation of observational results by "toroidal convection rolls" was proposed (Ribes et al 1985, Ribes andLaclare 1988).…”

Section: The Convective Motionsmentioning

confidence: 99%

The Solar Dynamo

Rädler¹

1990

International Astronomical Union Colloquium

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The phenomena of solar activity are connected with a general magnetic field of-the Sun which is due to a dynamo process essentially determined by the α-effect and the differential rotation in the convection zone. A few observational facts are summarized which are important for modelling this process. The basic ideas of the solar dynamo theory, with emphasis on the mean-field approach, are explained, and a critical review of the dynamo models investigated so far is given. Although several models reflect a number of essential features of the solar magnetic cycle there are many open questions. Part of them result from lack of knowledge of the structure of the convective motions and the differential rotation. Other questions concern, for example, details of the connection of the α-effect and related effects with the convective motions, or the way in which the behaviour of the dynamo is influenced by the back-reaction of the magnetic field on the motions.

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Toroidal convection rolls in the sun a challenge to theory

Cited by 19 publications

References 20 publications

Convection in the Sun

Convection in the Sun

On a Plausible Physical Mechanism Linking the Maunder Minimum to the Little Ice Age

The Solar Dynamo

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