Speaker
Serge Koutchmy
(Institut d'Astrophysique de Paris CNRS & UPMC)
Description
The free of seeing effects high resolution images of a
single sunspot observed near the centre of the Sun with the
SOT (Hinode) are accuratly deconvolved. The new PSF deduced
from the transit of Venus and from the extreme limb data
takes into account both the diffraction of origin smearing
and the stray light from the optics. It considerably
improved the details near the diffraction limit, including
the structure on penumbral and umbral features. A 45 min
movie was assembled showing a wealth of phenomena
reminiscent of the dynamical emerging magnetic field ropes
in the penumbra. It includes the proper motions of inwardly
moving and splitting peripheral and more central bright
umbral dots. The ubiquitous bright inner penumbra “ring” is
discussed with a possible interpretation of non radiative
origin. Outwardly moving dark features at the outer
boundaries of the penumbra seem reminiscent of the Evershed
effect and it is suggested that they correspond to the
moving magnetic features of the super- penumbra seen much
further out with magnetograms. A discussion of the possible
origin of outwardly propagating coherent penumbral waves is
also attempted. The magnetic structure at high coronal level
is finally discussed using extrapolations from the HMI(SDO)
magnetograms by making a comparison with EM structures
observed with the AIA (SDO) imager suggesting a non
potential force free approximation can be assumed in the
corona, in addition to a sub- photospheric ring current
dynamo model of a sunspot as proposed by Larmor and Alfven.
