Additional Evidence Supporting a Model of Shallow, High-Speed Supergranulation

Abstract

Recently, Duvall and Hanasoge ({\it Solar Phys.} {\bf 287}, 71-83, 2013) found that large distance $[\Delta ]$ separation travel-time differences from a center to an annulus $[\delta t_{\mathrm{oi}}]$ implied a model of the average supergranular cell that has a peak upflow of $240\mathrm{m}{\mathrm{s}}^{-1}$ at a depth of $2.3\mathrm{Mm}$ and a corresponding peak outward horizontal flow of $700\mathrm{m}{\mathrm{s}}^{-1}$ at a depth of $1.6\mathrm{Mm}$. In the present work, this effect is further studied by measuring and modeling center-to-quadrant travel-time differences $[\delta t_{\mathrm{qu}}]$, which roughly agree with this model. Simulations are analyzed that show that such a model flow would lead to the expected travel-time differences. As a check for possible systematic errors, the center-to-annulus travel-time differences $[\delta t_{\mathrm{oi}}]$ are found not to vary with heliocentric angle. A consistency check finds an increase of $\delta t_{\mathrm{oi}}$ with the temporal frequency $[\nu ]$ by a factor of two, which is not predicted by the ray theory.

References in corpus (11)

• Local Helioseismology: Three Dimensional Imaging of the Solar Interior
• The Sun's Supergranulation
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• Linear Sensitivity of Helioseismic Travel Times to Local Flows
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• Validated helioseismic inversions for 3-D vector flows
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• Impact of Locally Suppressed Wave sources on helioseismic travel times
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• Inversions for Average Supergranular Flows Using Finite-frequency Kernels

Cited by in corpus (13)

• Seismic Sounding of Convection in the Sun
• Relation between trees of fragmenting granules and supergranulation evolution
• Helioseismic Investigation of Modeled and Observed Supergranule Structure
• Evolution and wave-like properties of the average solar supergranule
• Time-Distance Helioseismology of Two Realistic Sunspot Simulations
• Combined helioseismic inversions for 3D vector flows and sound-speed perturbations
• Plasma flows and sound-speed perturbations in the average supergranule
• Probabilistic Inversions for Time-Distance Helioseismology
• Validating Forward Modeling and Inversions of Helioseismic Holography Measurements
• Iterative inversion of synthetic travel times successful at recovering sub-surface profiles of supergranular flows
• Characterizing the spatial pattern of solar supergranulation using the bispectrum
• Observational characterisation of large-scale transport and horizontal turbulent diffusivity in the quiet Sun
• Exploiting solar visible-range observations by inversion techniques: from flows in the solar subsurface to a flaring atmosphere