On searching for observational manifestations of Alfvén waves in solar faculae
| Autor: | A. A. Chelpanov, S. A. Chupin, N. I. Kobanov |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
Physics
010504 meteorology & atmospheric sciences Oscillation Phase (waves) Astronomy and Astrophysics Astrophysics 01 natural sciences Radio spectrum Spectral line Magnetic field Intensity (physics) Amplitude Space and Planetary Science 0103 physical sciences 010303 astronomy & astrophysics 0105 earth and related environmental sciences Line (formation) |
| Zdroj: | Astronomy Letters. 43:844-853 |
| ISSN: | 1562-6873 1063-7737 |
| DOI: | 10.1134/s1063773717110044 |
| Popis: | In an effort to detect torsional oscillations, we have studied the periodic half-width variations for several spectral lines in solar faculae. The duration of the series being analyzed was from 40 to 150 min. We have determined the dominant frequencies and amplitudes of the half-width oscillations and considered their phase relations to the intensity and line-of-sight velocity oscillations. Five-minute profile halfwidth oscillations with a peak-to-peak amplitude of ∼10 m ˚A are recorded with confidence in the upperphotospheric Si I 10 827 ˚A line in faculae. The chromospheric He I 10 830 A˚ and Hα line profiles shows ∼40–60 m ˚A variations in two frequency bands, 2.5–4 and 1–1.9 mHz. No center-to-limb dependence that, according to the theory, must accompany the torsional oscillations has been revealed in the behavior of the oscillation amplitudes. According to present views, these variations cannot be caused by periodic temperature and magnetic field changes. Our observations do not allow us to explain these variations by the sausage mode action either, which should manifest itself at the double frequency. |
| Databáze: | OpenAIRE |
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