Numerical Models of Travel-Time Inhomogeneities in Sunspots

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dc.creatorMoradi, H.
dc.creatorHanasoge, S. M.
dc.creatorCally, P. S.
dc.date2008-08-27
dc.date2008-11-09
dc.date.accessioned2026-07-07T12:15:21Z
dc.date.available2026-07-07T12:15:21Z
dc.descriptionWe investigate the direct contribution of strong, sunspot-like magnetic fields to helioseismic wave travel-time shifts via two numerical forward models, a 3D ideal MHD solver and MHD ray theory. The simulated data cubes are analyzed using the traditional time-distance center-to-annulus measurement technique. We also isolate and analyze the direct contribution from purely thermal perturbations to the observed travel-time shifts, confirming some existing ideas and bring forth new ones: (i) that the observed travel-time shifts in the vicinity of sunspots are largely governed by MHD physics, (ii) the travel-time shifts are sensitively dependent on frequency and phase-speed filter parameters and the background power below the $p_1$ ridge, and finally, (iii) despite its seeming limitations, ray theory succeeds in capturing the essence of the travel-time variations as derived from the MHD simulations.
dc.description13 Pages, 3 Figures. ApJ Letters Accepted
dc.identifierhttps://arxiv.org/abs/0808.3628
dc.identifierhttp://arxiv.org/abs/0808.3628
dc.identifierAstrophys.J.Lett.690:L72-L75,2009
dc.identifierdoi:10.1088/0004-637X/690/1/L72
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/211476
dc.subjectAstrophysics
dc.titleNumerical Models of Travel-Time Inhomogeneities in Sunspots
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