Subsurface Zonal Flows |
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| Authors: | R Komm R Howe F Hill I González Hernández |
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| Institution: | (1) National Solar Observatory, Tucson, AZ 85719, USA |
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| Abstract: | We study the zonal flow in solar subsurface layers, analyzing about six years of GONG++ high-resolution Doppler data with
ring-diagram analysis. We focus on the variation of zonal flow with magnetic activity over a range of depths from the surface
to about 16 Mm. There is a positive correlation between unsigned magnetic flux and zonal flow at most depths. We calculate
the average zonal flow for a quiet- and an active-region subset defined as dense-pack locations with an unsigned magnetic
flux less than 3.4 G and locations with greater than 65.0 G, respectively. The average zonal flow of active regions is about
4 m s−1 larger than the average flow of quiet regions. This difference increases slightly with increasing depth, which might be explained
by a nonradial inclination of the flux tubes or a different extent in depth of different magnetic features. The difference
shows no apparent pattern in time and latitude, which makes it unlikely that it is simply a manifestation of the torsional-oscillation
pattern. As a byproduct, we find that the size of the North – South asymmetry of the rotation rate decreases during the same
epoch. |
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| Keywords: | Active regions velocity field Helioseismology observations Interior convective zone Rotation Velocity fields interior |
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