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arXiv · 1002.2379

Surface magnetic field effects in local helioseismology

H. Schunker·D. C. Braun·P. S. Cally
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Abstract

Using helioseismic holography strong evidence is presented that the phase (or equivalent travel-time) of helioseismic signatures in Dopplergrams within sunspots depend upon the line-of-sight angle in the plane containing the magnetic field and vertical directions. This is shown for the velocity signal in the penumbrae of two sunspots at 3, 4 and 5 mHz. Phase-sensitive holography demonstrates that they are significantly affected in a strong, moderately inclined magnetic field. This research indicates that the effects of the surface magnetic field are potentially very significant for local helioseismic analysis of active regions.

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H. Schunker, D. C. Braun, P. S. Cally. 2010-02-11. Surface magnetic field effects in local helioseismology. https://doi.org/10.1002/asna.200610732

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