Measurement process and inversions using helioseismic normal-mode coupling

Abstract

Normal modes are coupled by the presence of perturbations in the Sun, providing a novel and under-appreciated helioseismic technique with which to image the solar interior. The process of measuring coupling between normal modes is straightforward, much more so when compared with other prevalent helioseismic techniques. The theoretical framework to interpret these measurements is well developed with the caveat that it applies only in the case where the entire surface of the Sun is observed. In practice however, the limited visibility of the Sun and line-of-sight related effects diminish the resolution of the technique. Here, we compute realistic sensitivities of normal-mode coupling measurements to flows in the solar interior and describe how to mitigate the sometimes-overwhelming effect of leakage. The importance of being able to isolate individual spherical harmonics and observe the full Sun, to which future solar observatories may aspire, is thus highlighted in our results. In the latter part of the article, we describe the noise model for the variance of coupling coefficients, a critical component to the process of inference.

23 pages, 11 figures, ApJ

References in corpus (2)

• Sensitivity of Helioseismic Measurements of Normal-mode Coupling to Flows and Sound-speed Perturbations
• Seismic sensitivity of Normal-mode Coupling to Lorentz stresses in the Sun

Cited by in corpus (5)

• Properties of solar Rossby waves from normal mode coupling and characterizing its systematics
• Detection of Rossby modes with even azimuthal orders using helioseismic normal-mode coupling
• Inferring solar differential rotation through normal-mode coupling using Bayesian statistics
• 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