A method for the treatment of supergranulation advection  
by giant cells

Williams, Peter; Cuntz, M.

doi:10.1051/0004-6361/200811499

Cited by 7 publications

(3 citation statements)

References 24 publications

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“…The manner in which we evolve the cells in the simulation is not fully satisfactory. The phase (and amplitude) changes associated with the evolving cells should replicate their advection by larger (nonaxysymmetric) flows (Williams & Cuntz 2009), their break-up into smaller cells, and their joining to form larger cells. The random changes in phase that we introduce to evolve the cells produces random offsets that are larger for larger wavenumbers and, when modulated by the power spectrum shown in Fig 3, produces the wedge of power shown in Fig 6 for the simulation.…”

Section: Discussionmentioning

confidence: 99%

The Advection of Supergranules by the Sun's Axisymmetric Flows

Hathaway

Williams

Rosa

et al. 2010

ApJ

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We show that the motions of supergranules are consistent with a model in which they are simply advected by the axisymmetric flows in the Sun's surface shear layer. We produce a 10day series of simulated Doppler images at a 15-minute cadence that reproduces most spatial and temporal characteristics seen in the SOHO/MDI Doppler data. Our simulated data have a spectrum of cellular flows with just two components -a granule component that peaks at spherical wavenumbers of about 4000 and a supergranule component that peaks at wavenumbers of about 110. We include the advection of these cellular components by the axisymmetric flowsdifferential rotation and meridional flow -whose variations with latitude and depth (wavenumber) are consistent with observations. We mimic the evolution of the cellular pattern by introducing random variations to the phases of the spectral components at rates that reproduce the levels of cross-correlation as functions of time and latitude. Our simulated data do not include any wavelike characteristics for the supergranules yet can reproduce the rotation characteristics previously attributed to wave-like behavior. We find rotation rates which appear faster than the actual rotation rates and attribute this to the projection effects. We find that the measured meridional flow does accurately represent the actual flow and that the observations indicate poleward flow to 65 • − 70 • latitude with equatorward counter cells in the polar regions.

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Section: Discussionmentioning

confidence: 99%

The Advection of Supergranules by the Sun's Axisymmetric Flows

Hathaway

Williams

Rosa

et al. 2010

ApJ

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“…Numerous attempts to detect the photospheric manifestations of predicted gigantic convective cells on the Sun, mainly with Doppler, astroseismic, and correlation tracking techniques, have been carried out with no conclusive results (Williams & Cuntz 2009;Hanasoge et al 2010).…”

Section: Introductionmentioning

confidence: 99%

Signs of deep mixing in starspot variability

Arkhypov

Khodachenko

Güdel

et al. 2015

A&A

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The current knowledge on plasma mixing in stellar interiors is based on theoretical modeling, which calibrates the empirical relations between the mixing and observable stellar parameters. Hence, a model-independent method of studying the mixing process is a desirable, but yet unfounded approach. Here, using a new spectral-correlation method, verified for the Sun, we show that deep mixing is manifested in stellar photometric light curves. We measure the timescales of the stochastic change in the spectral power of rotational variability of hundreds of main-sequence stars from the Kepler mission archive. The discovered proportionality of these timescales to the turnover time of the standard mixing length theory, their consistency with Kolmogorov's theory of turbulence, and the relation with stellar activity provide a new approach to the probing of stellar interiors. This opens a broad perspective for experimental studies of deep mixing and magnetic dynamos in stars.

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“…Numerous attempts to detect photospheric manifestations of deep convection (mainly gigantic cells) were carried so far with no definitive results [Williams and Cuntz, 2009]. That is why the consideration of new approaches in that respect seems to be an actual task.…”

Section: Introductionmentioning

confidence: 99%

Millimeter Radio Astronomy and the Solar Convection Zone

Arkhypov¹,

Antonov²,

Khodachenko³

2011

Planetary Radio Emissions Vii

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The global distribution of solar surface activity (active regions) is connected with processes in the convection zone. To extract the information on large-scale motions in the convection zone, we study the solar synoptic charts (Mount Wilson 1998-2004, Fe I, 525.02 nm). The clear indication of large-scale (≥ 18 o) turbulence is found. This may be a manifestations of the deep convection because there is no such global turbulent eddies in the solar photosphere. The preferred scales of longitudinal variations in surface solar activity are revealed. These correspond to ∼ 15 o to 51 o (gigantic convection cells), 90 o , 180 o and 360 o. Similar scales (e.g., 40 o and 90 o) are found in the millimeter radio-images (Metsähovi Radio Observatory 1994-1998, 37 and 87 GHz). Hence, the millimeter radio astronomy could prove useful for remote sensing of the solar convection zone.

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A method for the treatment of supergranulation advection by giant cells

Cited by 7 publications

References 24 publications

The Advection of Supergranules by the Sun's Axisymmetric Flows

The Advection of Supergranules by the Sun's Axisymmetric Flows

Signs of deep mixing in starspot variability

Millimeter Radio Astronomy and the Solar Convection Zone

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