Analyzing supergranular power spectra using helioseismic normal-mode coupling

Abstract

Normal-mode coupling is a technique applied to probe the solar interior using surface observations of oscillations. The technique, which is straightforward to implement, makes more use of the seismic information in the wavefield than other comparable local imaging techniques and therefore has the potential to significantly improve current capabilities. Here, we examine supergranulation power spectra using mode-coupling analyses of intermediate-to-high-degree modes by invoking a Cartesian-geometric description of wave propagation under the assumption that the localized patches are much smaller in size than the solar radius. We extract the supergranular power spectrum and compare the results with prior helioseismic studies. Measurements of the dispersion relation and life times of supergranulation, obtained using near surface modes (f and p${}_1$), are in accord with the literature. We show that the cross-coupling between the p${}_2$ and p${}_3$ acoustic modes, which are capable of probing greater depths, are also sensitive to supergranulation.

7 pages, 3 figures, Accepted into ApJ

References in corpus (12)

• Helioseismology
• Local Helioseismology: Three Dimensional Imaging of the Solar Interior
• Global-scale equatorial Rossby waves as an essential component of solar internal dynamics
• Solar supergranulation as a wavelike phenomenon
• Ring diagram analysis of near-surface flows in the Sun
• The Role of Subsurface Flows in Solar Surface Convection: Modeling the Spectrum of Supergranular and Larger Scale Flows
• Spatially resolved vertical vorticity in solar supergranulation using helioseismology and local correlation tracking
• Subsurface Supergranular Vertical Flows as Measured Using Large Distance Separations in Time-Distance Helioseismology
• Evidence for Large-Scale Subsurface Convection in the Sun
• Sensitivity of Helioseismic Measurements of Normal-mode Coupling to Flows and Sound-speed Perturbations
• Evolution and wave-like properties of the average solar supergranule
• Seismic sensitivity of Normal-mode Coupling to Lorentz stresses in the Sun

Cited by in corpus (5)

• Detection of Rossby modes with even azimuthal orders using helioseismic normal-mode coupling
• Imaging the Sun's near-surface flows using mode-coupling analysis
• Recipe for inferring sub-surface solar magnetism via local mode-coupling using Slepian basis functions
• Investigating toroidal flows in the Sun using normal-mode coupling
• Testing volume integrals of travel-time sensitivity kernels for flows