Bibcode
Felipe, T.; Socas-Navarro, H.; Khomenko, E.
Bibliographical reference
The Astrophysical Journal, Volume 795, Issue 1, article id. 9, 18 pp. (2014).
Advertised on:
11
2014
Journal
Citations
27
Refereed citations
26
Description
Spectropolarimetric temporal series from Fe I λ6301.5 Å
and Ca II infrared triplet lines are obtained by applying the Stokes
synthesis code NICOLE to a numerical simulation of wave propagation in a
sunspot umbra from MANCHA code. The analysis of the phase difference
between Doppler velocity and intensity core oscillations of the Fe I
λ6301.5 Å line reveals that variations in the intensity
are produced by opacity fluctuations rather than intrinsic temperature
oscillations, except for frequencies between 5 and 6.5 mHz. On the other
hand, the photospheric magnetic field retrieved from the weak field
approximation provides the intrinsic magnetic field oscillations
associated to wave propagation. Our results suggest that this is due to
the low magnetic field gradient of our sunspot model. The Stokes
parameters of the chromospheric Ca II infrared triplet lines show
striking variations as shock waves travel through the formation height
of the lines, including emission self-reversals in the line core and
highly abnormal Stokes V profiles. Magnetic field oscillations inferred
from the Ca II infrared lines using the weak field approximation appear
to be related with the magnetic field strength variation between the
photosphere and the chromosphere.
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