INVESTIGADORES
MANDRINI Cristina Hemilse
congresos y reuniones científicas
Título:
Active regions twist from magnetic tongues and force-free coronal models
Autor/es:
LÓPEZ FUENTES, M.C.; POISSON, M.; MANDRINI, C.H.; DÉMOULIN, P.
Lugar:
Cuzco
Reunión:
Congreso; X Conferencia Latinoamericana de Geofísica Espacial; 2014
Institución organizadora:
Asociación Latinoamericana de Geofísca Espacial - International Space Weather Initiative
Resumen:
The magnetic flux distribution observed in photospheric
magnetograms provide valuable information about the characteristics of the
magnetic structures that originate active regions (ARs). This is the case of
the so-called magnetic tongues, that appear in bipolar AR magnetograms as
deformations of the main polarities. They are due to the projection, in the
direction normal to the photosphere, of the azimuthal component of the magnetic
field around the main axis of twisted toroidal flux-tubes that emerge from the
solar interior. In a recent work, we developed a new method to characterize the
effect of magnetic tongues in bipolar ARs by computing and analizing the
evolution of the AR polarity inversion line (PIL). Here, we use the PIL
technique to infer the twist of a set of ARs observed with SOHO/MDI, assuming
that they are formed by twisted toroidal magnetic flux-tubes. We use as a proxy
of the twist the number of turns of the magnetic field lines around the tube's
axis. To test the procedure we compare our findings with the twist obtained
from linear force-free field models of the AR coronal structures observed in
EUV. From our results we confirm that the the method based on the PIL is a
robust and reliable way to obtain an early indicator of the twist content in
ARs. (See also the poster "Statistical analysis of magnetic twist
properties of ARs from magnetic tongues" by Poisson et al., presented in
this meeting).