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 (3)

• Linear Sensitivity of Helioseismic Travel Times to Local Flows
• High-resolution mapping of flows in the solar interior: Fully consistent OLA inversion of helioseismic travel times
• Impact of Locally Suppressed Wave sources on helioseismic travel times

Cited by in corpus (5)

• Helioseismic Investigation of Modeled and Observed Supergranule Structure
• 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
• Iterative inversion of synthetic travel times successful at recovering sub-surface profiles of supergranular flows