| Autor: |
Kobanov, N. I., Kolobov, D. Y., Chupin, S. A., Nakariakov, V. M. |
| Rok vydání: |
2011 |
| Předmět: |
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| Zdroj: |
Astronomy & Astrophysics, 525, A41 (2011) |
| Druh dokumentu: |
Working Paper |
| DOI: |
10.1051/0004-6361/200913533 |
| Popis: |
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 H-alpha 6563{\AA} and FeI 6569{\AA} 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. |
| Databáze: |
arXiv |
| Externí odkaz: |
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