Bibcode
Zhao, J.; Felipe, T.; Chen, R.; Khomenko, E.
Bibliographical reference
The Astrophysical Journal Letters, Volume 830, Issue 1, article id. L17, 7 pp. (2016).
Advertised on:
10
2016
Citations
30
Refereed citations
29
Description
Atmosphere above sunspots is abundant with different types of waves.
Among these waves are running penumbral waves in the chromosphere,
quasi-periodic oscillations in the lower coronal loops, and recently
reported running waves in sunspots’ photosphere, all of which were
interpreted as magnetoacoustic waves by some authors. Are these waves in
different atmospheric layers related to each other, what is the nature
of these waves, and where are the ultimate sources of these waves?
Applying a time–distance helioseismic analysis over a suite of
multi-wavelength observations above a sunspot, we demonstrate that the
helioseismic p-mode waves are able to channel up from the photosphere
through the chromosphere and transition region into the corona, and that
the magnetoacoustic waves observed in different atmospheric layers are a
same wave originating from the photosphere but exhibiting differently
under different physical conditions. We also show waves of different
frequencies travel along different paths, which can be used to derive
the physical properties of the atmosphere above sunspots. Our numerical
simulation of traveling of waves from a subphotospheric source
qualitatively resembles the observed properties of the waves and offers
an interpretation of the shapes of the wavefronts above the photosphere.