Height distribution of the power of 3-min oscillations over sunspots
Kobanov, N. I., Kolobov, D. Y., Chupin, S. A. and Nakariakov, Valery M.. (2011) Height distribution of the power of 3-min oscillations over sunspots. Astronomy & Astrophysics, Vol.525 . Article no. A41. ISSN 0004-6361Full text not available from this repository.
Official URL: http://dx.doi.org/10.1051/0004-6361/200913533
Context. The height structure of 3-min oscillations over sunspots is studied in the context of the recently discovered effect of height inversion: over the umbra, the spatial location of the maximum of chromospheric 3-min oscillation power corresponds to the relative decrease in the power of photospheric oscillations. Aims. We investigate whether the height inversion of the power of 3-min oscillations is a common feature of the spatial structure of the oscillations for the majority of sunspots. Methods. Spectrogram sequences of Ha 6563 angstrom and Fe I 6569 angstrom over sunspots, acquired with very high cadency (about 2 s or better) are obtained. The distribution of the oscillation power of the line-of-sight velocity signal is studied by using methods of wavelet frequency filtration and Fourier analysis. Results. The effect of the height inversion is found in 9 of 11 analyzed active regions. The interpretation of this effect is possibly connected to both the decrease in the level of photosphere in sunspot umbrae and the magnetic field topology.
|Item Type:||Journal Article|
|Subjects:||Q Science > QB Astronomy|
|Divisions:||Faculty of Science > Physics|
|Journal or Publication Title:||Astronomy & Astrophysics|
|Number of Pages:||5|
|Page Range:||Article no. A41|
|Access rights to Published version:||Restricted or Subscription Access|
|Funder:||Royal Society (Great Britain), Federal Agency for Science and Innovation|
|Grant number:||10-02-00153-a (Royal Society) ; 02.740.11.0576, RFBR 08-02-91860-KO_a (Federal Agency for Science and Innovation)|
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