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Small-scale motions over concentrated magnetic regions of the quiet Sun
Authors:H C Dara  C E Alissandrakis  S Koutchmy
Institution:1. Research Center for Astr. and Appl.-Math., 14 Anagnostopoulou Street, 10673, Athens, Greece
2. Section of Astrophysics, Astronomy and Mechanics, Department of Physics, University of Athens, GR-15783, Athens, Greece
3. Institut d'Astrophysique CNRS, 98 bis, Bd Arago, F-75014, Paris, France
Abstract:We have used a 5.5 min time-sequence of spectra in the Fe i lines λ5576 (magnetically insensitive), λ6301.5 and λ6302.5 (magnetically sensitive) to study the association of concentrated magnetic regions and velocity in the quiet Sun. After the elimination of photospheric oscillations we found downflows of 100–300 m s ?1, displaced by about 2″ from the peaks of the magnetic field; this velocity is comparable to downflow velocity associated with the granulation and of the same order or smaller than the oscillation amplitude. Quasi-periodic time variations of the vertical component of the magnetic field up to ± 40% were also found with a period near 250 s, close to the values found for the velocity field. Finally we report a possible association of intensity maxima at the line center with peaks of the oscillation amplitude.
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