Bibcode
Parchevsky, K.; Kosovichev, A.; Khomenko, E.; Olshevsky, V.; Collados, M.
Bibliographical reference
Highlights of Astronomy, Volume 15, p. 354-354
Advertised on:
11
2010
Citations
2
Refereed citations
1
Description
We present results of numerical 3D simulation of propagation of MHD
waves in sunspots. We used two self consistent magnetohydrostatic
background models of sunspots. There are two main differences between
these models: (i) the topology of the magnetic field and (ii) dependence
of the horizontal profile of the sound speed on depth. The model with
convex shape of the magnetic field lines near the photosphere has
non-zero horizorntal perturbations of the sound speed up to the depth of
7.5 Mm (deep model). In the model with concave shape of the magnetic
field lines near the photosphere Δ c/c is close to zero everywhere
below 2 Mm (shallow model). Strong Alfven wave is generated at the wave
source location in the deep model. This wave is almost unnoticeable in
the shallow model. Using filtering technique we separated
magnetoacoustic and magnetogravity waves. It is shown, that inside the
sunspot magnetoacoustic and magnetogravity waves are not spatially
separated unlike the case of the horizontally uniform background model.
The sunspot causes anisotropy of the amplitude distribution along the
wavefront and changes the shape of the wavefront. The amplitude of the
waves is reduced inside the sunspot. This effect is stronger for the
magnetogravity waves than for magnetoacoustic waves. The shape of the
wavefront of the magnetogravity waves is distorted stronger as well. The
deep model causes bigger anisotropy for both mgnetoacoustic and magneto
gravity waves than the shallow model.