J. Palacios, J. Blanco Rodríguez, S. Vargas Domínguez, V. Domingo, V. Martínez Pillet, J. A. Bonet, L. R. Bellot Rubio, J. C. del Toro Iniesta, S. K. Solanki, P. Barthol, A. Gandorfer, T. Berkefeld, W. Schmidt, M. Knölker
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 $\sim$ 10$^{18}$ Mx of magnetic flux emerges. The emergence of
weak unipolar longitudinal fields ($\sim$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 while magnetic patches expand at
0.65 \kms. 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.
View original:
http://arxiv.org/abs/1110.4555
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