TY - JOUR
T1 - Helioseismology of sunspots
T2 - How sensitive are travel times to the Wilson depression and to the subsurface magnetic field?
AU - Schunker, H.
AU - Gizon, L.
AU - Cameron, R. H.
AU - Birch, A. C.
N1 - Funding Information:
H.S. and L.G. acknowledge research funding by Deutsche Forschungsgemeinschaft (DFG) under grant SFB 963/1 “Astrophysical flow instabilities and turbulence” (Project A18, WP “Seismology of magnetic activity”). The German Data Center for SDO, funded by the German Aerospace Center (DLR), provided the IT infrastructure.
PY - 2013
Y1 - 2013
N2 - To assess the ability of helioseismology to probe the subsurface structure and magnetic field of sunspots, we need to determine how helioseismic travel times depend on perturbations to sunspot models. Here we numerically simulate the propagation of f, p1, and p2 wave packets through magnetic sunspot models. Among the models we considered, a ±50 km change in the height of the Wilson depression and a change in the subsurface magnetic field geometry can both be detected above the observational noise level. We also find that the travel-time shifts due to changes in a sunspot model must be modeled by computing the effects of changing the reference sunspot model, and not by computing the effects of changing the subsurface structure in the quiet-Sun model. For p1 modes, the latter is wrong by a factor of four. In conclusion, numerical modeling of MHD wave propagation is an essential tool for interpreting the effects of sunspots on seismic waveforms.
AB - To assess the ability of helioseismology to probe the subsurface structure and magnetic field of sunspots, we need to determine how helioseismic travel times depend on perturbations to sunspot models. Here we numerically simulate the propagation of f, p1, and p2 wave packets through magnetic sunspot models. Among the models we considered, a ±50 km change in the height of the Wilson depression and a change in the subsurface magnetic field geometry can both be detected above the observational noise level. We also find that the travel-time shifts due to changes in a sunspot model must be modeled by computing the effects of changing the reference sunspot model, and not by computing the effects of changing the subsurface structure in the quiet-Sun model. For p1 modes, the latter is wrong by a factor of four. In conclusion, numerical modeling of MHD wave propagation is an essential tool for interpreting the effects of sunspots on seismic waveforms.
KW - Sun: helioseismology
KW - Sunspots
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U2 - 10.1051/0004-6361/201321485
DO - 10.1051/0004-6361/201321485
M3 - Article
AN - SCOPUS:84886576697
SN - 0004-6361
VL - 558
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
M1 - A130
ER -