Bibcode
Palacios, J.; Blanco Rodríguez, J.; Vargas Domínguez, S.; Domingo, V.; Martínez-Pillet, V.; Bonet, J. A.; Bellot Rubio, L. R.; Del Toro Iniesta, J. C.; Solanki, S. K.; Barthol, P.; Gandorfer, A.; Berkefeld, T.; Schmidt, W.; Knölker, M.
Bibliographical reference
Astronomy and Astrophysics, Volume 537, id.A21
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1
2012
Journal
Citations
24
Refereed citations
20
Description
We report on magnetic field emergences covering significant areas of
exploding granules. The balloon-borne mission Sunrise provided high
spatial and temporal resolution images of the solar photosphere.
Continuum images, longitudinal and transverse magnetic field maps and
Dopplergrams obtained by IMaX onboard Sunrise are analyzed by local
correlation traking (LCT), divergence calculation and time slices,
Stokes inversions and numerical simulations are also employed. We
characterize two mesogranular-scale exploding granules where
~1018 Mx of magnetic flux emerges. The emergence of weak
unipolar longitudinal fields (~100 G) start with a single visible
magnetic polarity, occupying their respective granules' top and
following the granular splitting. After a while, mixed polarities start
appearing, concentrated in downflow lanes. The events last around 20
min. LCT analyses confirm mesogranular scale expansion, displaying a
similar pattern for all the physical properties, and divergence centers
match between all of them. We found a similar behaviour with the
emergence events in a numerical MHD simulation. Granule expansion
velocities are around 1 kms-1 while magnetic patches expand
at 0.65 kms-1. One of the analyzed events evidences the
emergence of a loop-like structure. Advection of the emerging magnetic
flux features is dominated by convective motion resulting from the
exploding granule due to the magnetic field frozen in the granular
plasma. Intensification of the magnetic field occurs in the
intergranular lanes, probably because of being directed by the
downflowing plasma.
Movies associated to Figs. 2-4 are available in electronic form at http://www.aanda.org
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