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Paper: Subsurface Flows Near Active Regions and Filaments as Determined by Local Helioseismology
Volume: 383, Subsurface and Atmospheric Influences on Solar Activity
Page: 31
Authors: Haber, D.A.
Abstract: Subsurface flows, determined by local-helioseismic techniques such as time-distance tomography, ring analysis, and acoustic holography, are often stronger and more organized near magnetic activity than in areas of quiet Sun. Markedly different behavior is seen depending on the strength of magnetic activity and depth of observed flows. On the larger scales generally used by ring-analysis techniques, converging flows are seen near the surface around most active regions, while diverging flows are seen below 10 Mm for the largest complexes. On smaller scales — those used mainly by time-distance tomography, acoustic holography, and high-resolution ring analysis — diverging moat flows are observed in the near-surface layers around sunspots. This paper is a review of what we have learned so far about long-lasting flows (≥ 8h) in and around active regions, as determined by the various local helioseismic techniques, as well as how these flows may influence magnetic structures and activity higher in the solar atmosphere.
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