Oscillations accompanying a He I 10830 {\AA} negative flare in a solar facula
| Autor: | A. A. Chelpanov, N. I. Kobanov |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
Facula
Physics Photosphere 010504 meteorology & atmospheric sciences Solar flare Astrophysics::High Energy Astrophysical Phenomena Astronomy and Astrophysics Astrophysics 01 natural sciences Spectral line law.invention Amplitude Astrophysics - Solar and Stellar Astrophysics Space and Planetary Science law 0103 physical sciences Physics::Space Physics Astrophysics::Solar and Stellar Astrophysics 010303 astronomy & astrophysics Chromosphere 0105 earth and related environmental sciences Line (formation) Flare |
| Popis: | On 21 September 2012, we carried out spectral observations of a solar facula in the Si i 10827 A, He i 10830 A, and H $\upalpha$ spectral lines. Later, in the process of analyzing the data, we found a small-scale flare in the middle of the time series. Based on the anomalous increase in the absorption of the He i 10830 A line, we identified this flare as a negative flare. The aim of this article is to study the influence of the negative flare on the oscillation characteristics in the facular photosphere and chromosphere. We measured the line-of-sight (LOS) velocity and intensity of all the three lines as well as the half-width of the chromospheric lines. We also used the Helioseismic and Magnetic Imager (HMI) magnetic field data. The flare caused a modulation of all these parameters. In the location of the negative flare, the amplitude of the oscillations increased four times on average. In the adjacent magnetic field local maxima, the chromospheric LOS velocity oscillations appreciably decreased during the flare. The facular region oscillated as a whole with a 5-minute period before the flare, and this synchronicity was disrupted after the flare. The flare changed the spectral composition of the LOS magnetic field oscillations, causing an increase in the low-frequency oscillation power. |
| Databáze: | OpenAIRE |
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