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Paper: Local Helioseismology and Magnetic Flux Emergence
Volume: 383, Subsurface and Atmospheric Influences on Solar Activity
Page: 59
Authors: Kosovichev, A.G.; Duvall, T.L. Jr.
Abstract: Investigations of emerging magnetic flux are important for understanding the basic properties of solar magnetism (such as the depth of the solar dynamo processes and “nests” of solar activity, formation of sunspots and active regions, organization of solar activity on various spatial and temporal scales), and also for forecasting solar activity and space weather. Local helioseismology is capable of detecting emerging magnetic flux in the solar interior, and determining variations of the sound speed and large-scale flows caused by the emerging flux. The initial results obtained by time-distance helioseismology for large emerging active regions reveal unexpected properties of the flux emergence and challenge the current theories and models. In this paper, we present results for AR 10488, which was observed from SOHO/MDI in October 2003. In particular, it is found that the magnetic flux propagates very rapidly in the upper convective zone. The active regions are a result of multiple flux emergence events, occurring in the region of the Sun during a period at least several days long. The emergence is accompanied by strong localized shearing outflows. However, no large-scale diverging flow pattern or significant upflows are detected prior to the emergence. The initial analysis shows that it is necessary to develop special local helioseismology methodology and theoretical models for studying fast dynamical processes associated with magnetic flux emergence.
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