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| Preflare very long-periodic pulsations observed in H alpha emission before the onset of a solar flare | |
| Alternative Title | WOS:000552060400003;20203008977880 |
| Li, Dong1,2; Feng, Song3; Su, Wei4; Huang, Yu | |
| Source Publication | ASTRONOMY & ASTROPHYSICS
 |
| 2020 | |
| Volume | 639Pages:L5 |
| DOI | 10.1051/0004-6361/202038398 |
| ISSN | 0004-6361 |
| Language | 英语 |
| Keyword | Sun: flares Sun: oscillations Sun: chromosphere Sun: UV radiation Sun: X-rays gamma rays CORONAL LOOP OSCILLATIONS RAY EMISSION MICROWAVE SIGNATURE DYNAMICS PLASMA WAVES SUMER |
| Abstract | Context. Very long-periodic pulsations during preflare phases (preflare-VLPs) have been detected in the full-disk solar soft X-ray (SXR) flux. They may be regarded as precursors to solar flares and may help us better understand the trigger mechanism of solar flares.Aims. In this Letter, we report a preflare-VLP event prior to the onset of an M1.1 circular-ribbon flare on 2015 October 16. It was simultaneously observed in H alpha, SXR, and extreme ultraviolet (EUV) wavelengths.Methods. The SXR fluxes in 1-8 angstrom and 1-70 angstrom were recorded by the Geostationary Operational Environmental Satellite (GOES) and Extreme Ultraviolet Variability Experiment, respectively; the light curves in H alpha and EUV 211 angstrom were integrated over a small local region, which were measured by the 1 m New Vacuum Solar Telescope and the Atmospheric Imaging Assembly (AIA), respectively. The preflare-VLP is identified as the repeat and quasi-periodic pulses in light curves during preflare phase. The quasi-periodicity can be determined from the Fourier power spectrum with Markov chain Monte Carlo-based Bayesian.Results. Seven well-developed pulses are found before the onset of an M1.1 circular-ribbon flare. They are firstly seen in the local light curve in H alpha emission and then discovered in full-disk SXR fluxes in GOES 1-8 angstrom and ESP 1-70 angstrom, as well as the local light curve in AIA 211 angstrom. These well-developed pulses can be regarded as the preflare-VLP, which might be modulated by LRC-circuit oscillation in the current-carrying plasma loop. The quasi-period is estimated to be similar to 9.3 min.Conclusions. We present the first report of a preflare-VLP event in the local H alpha line and EUV wavelength, which could be considered a precursor of a solar flare. This finding should therefore prove useful for the prediction of solar flares, especially for powerful flares. |
| Indexed By | SCI ; EI |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.nssc.ac.cn/handle/122/7703 |
| Collection | 中国科学院国家空间科学中心 |
| Affiliation | 1.Chinese Acad Sci, Key Lab Dark Matter & Space Astron, Purple Mt Observ, Nanjing 210033, Peoples R China 2.Chinese Acad Sci, State Key Lab Space Weather, Beijing 100190, Peoples R China 3.Natl Astron Observ, CAS Key Lab Solar Act, Beijing 100101, Peoples R China 4.Kunming Univ Sci & Technol, Fac Informat Engn & Automat, Yunnan Key Lab Comp Technol Applicat, Kunming 650500, Yunnan, Peoples R China 5.Huazhong Univ Sci & Technol, MOE Key Lab Fundamental Phys Quant Measurements, Sch Phys, Wuhan 430074, Peoples R China |
| Recommended Citation GB/T 7714 | Li, Dong,Feng, Song,Su, Wei,et al. Preflare very long-periodic pulsations observed in H alpha emission before the onset of a solar flare[J]. ASTRONOMY & ASTROPHYSICS,2020,639:L5. |
| APA | Li, Dong,Feng, Song,Su, Wei,&Huang, Yu.(2020).Preflare very long-periodic pulsations observed in H alpha emission before the onset of a solar flare.ASTRONOMY & ASTROPHYSICS,639,L5. |
| MLA | Li, Dong,et al."Preflare very long-periodic pulsations observed in H alpha emission before the onset of a solar flare".ASTRONOMY & ASTROPHYSICS 639(2020):L5. |
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