Bibcode
Manso-Sainz, R.; Martínez-González, M. J.; Asensio-Ramos, A.
Bibliographical reference
Astronomy and Astrophysics, Volume 531, id.L9
Advertised on:
7
2011
Journal
Citations
45
Refereed citations
37
Description
We track small magnetic structures on very quiet regions (internetwork)
of the Sun. We follow the footpoints of small-scale magnetic loops that
appear on the photosphere at granular scales using spectropolarimetric
and magnetographic data obtained with Hinode. We find two different
regimes for their wanderings. Within granules (where they appear), they
seem to be passively advected by the plasma - which is justified by
their relatively low magnetic flux (~1016 Mx), and magnetic
field strength (~200 G). The plasma flow thus traced is roughly laminar
with a characteristic mean velocity of 2 km s-1 and very low
vorticity. Once the magnetic markers reach intergranular lanes, they
remain there and are buffeted by the random flows of neighbouring
granules and turbulent intergranules, follow random walks, and disperse
across the solar surface with a diffusion constant of 195 km2
s-1. While on their intergranular random walking, they may
fall close to whirlpools (on scales ≲400 km) associated with
convective downdrafts, similar to the events recently reported in
mesogranular and supergranular cell boundaries tracking magnetic bright
points, which provides additional evidence that these events are
ubiquitous on the solar surface.
Related projects
Solar and Stellar Magnetism
Magnetic fields are at the base of star formation and stellar structure and evolution. When stars are born, magnetic fields brake the rotation during the collapse of the mollecular cloud. In the end of the life of a star, magnetic fields can play a key role in the form of the strong winds that lead to the last stages of stellar evolution. During
Tobías
Felipe García
Magnetism, Polarization and Radiative Transfer in Astrophysics
Magnetic fields pervade all astrophysical plasmas and govern most of the variability in the Universe at intermediate time scales. They are present in stars across the whole Hertzsprung-Russell diagram, in galaxies, and even perhaps in the intergalactic medium. Polarized light provides the most reliable source of information at our disposal for the
Tanausú del
Pino Alemán