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Paper: Investigating The Role of Strong Magnetic Fields on Helioseismic Wave Propagation
Volume: 416, Solar-Stellar Dynamos as Revealed by Helio- and Asteroseismology: GONG 2008/SOHO 21
Page: 143
Authors: Moradi, H.; Hanasoge, S. M.; Cally, P. S.
Abstract: We 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. We confirm 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 p1 mode, and finally, (iii) despite its seeming limitations, MHD ray theory appears to succeed in capturing the essence of the travel-time variations as derived from the MHD simulations.
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