Title: Magnetic loop emergence within a granule.
Authors: P. Gomory, C. Beck, H. Balthasar, J. Rybak, A. Kucera, J. Koza, H. Wohl
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Description: We investigated the temporal evolution of a small-scale magnetic loop emerging within a granule in the quiet-Sun internetwork. Although direct measurements of the 3D topology and the temporal evolution of such magnetic loops have already been reported in the past, to our knowledge this is the first time that they have been carried out successfully from a ground-based facility (VTT). The ~12 min episode of loop occurrence is illustrated in the Figure. In the early phases, a horizontal magnetic field with a distinct linear polarization signal dominated the emerging flux. Later on, two patches of opposite circular polarization signal appeared symmetrically on either side of the linear polarization patch, indicating a small loop-like structure. The middle part of the appearing feature was blueshifted during its occurrence, which also supports the scenario of an emerging loop. The mean magnetic flux density of this loop was roughly 450 G, with a total magnetic flux of around 3x10^(17) Mx. For unambiguous interpretation of observations we also created a simplified model of a rising loop in 3D. A comparison of the observed Stokes profiles with those arising from a model shows general qualitative (and in some particular cases even quantitative) agreement, proving that the observed event can be explained as a case of flux emergence in the shape of a small-scale loop.
Reference: Astronomy & Astrophysics 511, A14 (2010)
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Date and Time: 22.2. 2018 13:19:33 CET
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