High-frequency Oscillations in the Atmosphere above a Sunspot Umbra
文献类型：期刊论文
| 作者 | Wang, Feng2,3; Deng, Hui2; Li, Bo4; Feng, Song2,3; Bai, Xianyong1; Deng, Linhua5; Yang, Yunfei3; Xue, Zhike5; Wang, Rui5 |
| 刊名 | ASTROPHYSICAL JOURNAL LETTERS
 |
| 出版日期 | 2018-03-20 |
| 卷号 | 856期号:1页码:8 |
| 关键词 | magnetohydrodynamics (MHD) - sunspots Supporting material animation |
| ISSN号 | 2041-8205 |
| DOI | 10.3847/2041-8213/aab4f3 |
| 英文摘要 | We use high spatial and temporal resolution observations, simultaneously obtained with the New Vacuum Solar Telescope and Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory, to investigate the high-frequency oscillations above a sunspot umbra. A novel time-frequency analysis method, namely, the synchrosqueezing transform (SST), is employed to represent their power spectra and to reconstruct the high-frequency signals at different solar atmospheric layers. A validation study with synthetic signals demonstrates that SST is capable of resolving weak signals even when their strength is comparable to the high-frequency noise. The power spectra, obtained from both SST and the Fourier transform, of the entire umbral region indicate that there are significant enhancements between 10 and 14 mHz (labeled as 12 mHz) at different atmospheric layers. Analyzing the spectrum of a photospheric region far away from the umbra demonstrates that this 12 mHz component exists only inside the umbra. The animation based on the reconstructed 12 mHz component in AIA 171 angstrom illustrates that an intermittently propagating wave first emerges near the footpoints of coronal fan structures, and then propagates outward along the structures. A time-distance diagram, coupled with a subsonic wave speed (similar to 49 km s(-1)), highlights the fact that these coronal perturbations are best described as upwardly propagating magnetoacoustic slow waves. Thus, we first reveal the high-frequency oscillations with a period around one minute in imaging observations at different height above an umbra, and these oscillations seem to be related to the umbral perturbations in the photosphere. |
| 资助项目 | National Natural Science Foundation of China[11463003] ; National Natural Science Foundation of China[11503080] ; National Natural Science Foundation of China[11761141002] ; National Natural Science Foundation of China[41474149] ; National Natural Science Foundation of China[41674172] ; NSFC[U1531132] ; NSFC[U1531140] ; NSFC[U1631129] ; National Key Research and Development Program of China[U1531132] ; National Key Research and Development Program of China[U1531140] ; National Key Research and Development Program of China[U1631129] ; National Key Research and Development Program of China[2016YFE0100300] ; CAS Key Laboratory of Solar Activity of National Astronomical Observatories[KLSA201715] |
| WOS研究方向 | Astronomy & Astrophysics |
| 语种 | 英语 |
| WOS记录号 | WOS:000428392300007 |
| 出版者 | IOP PUBLISHING LTD |
| 资助机构 | National Natural Science Foundation of China ; NSFC ; National Key Research and Development Program of China ; CAS Key Laboratory of Solar Activity of National Astronomical Observatories ; National Natural Science Foundation of China ; NSFC ; National Key Research and Development Program of China ; CAS Key Laboratory of Solar Activity of National Astronomical Observatories ; National Natural Science Foundation of China ; NSFC ; National Key Research and Development Program of China ; CAS Key Laboratory of Solar Activity of National Astronomical Observatories ; National Natural Science Foundation of China ; NSFC ; National Key Research and Development Program of China ; CAS Key Laboratory of Solar Activity of National Astronomical Observatories |
| 源URL | [http://ir.bao.ac.cn/handle/114a11/35672]  |
| 专题 | 中国科学院国家天文台 |
| 通讯作者 | Feng, Song |
| 作者单位 | 1.Natl Astron Observ, CAS Key Lab Solar Act, Beijing 100012, Peoples R China 2.Guangzhou Univ, Sch Phys & Elect Engn, Guangzhou 510006, Guangdong, Peoples R China 3.Kunming Univ Sci & Technol, Fac Informat Engn & Automat, Yunnan Key Lab Comp Technol Applicat, Kunming 650500, Yunnan, Peoples R China 4.Shandong Univ, Inst Space Sci, Shandong Prov Key Lab Opt Astron & Solar Terr Env, Weihai 264209, Peoples R China 5.Chinese Acad Sci, Yunnan Observ, Kunming 650216, Yunnan, Peoples R China |
| 推荐引用方式 GB/T 7714 | Wang, Feng,Deng, Hui,Li, Bo,et al. High-frequency Oscillations in the Atmosphere above a Sunspot Umbra[J]. ASTROPHYSICAL JOURNAL LETTERS,2018,856(1):8. |
| APA | Wang, Feng.,Deng, Hui.,Li, Bo.,Feng, Song.,Bai, Xianyong.,...&Wang, Rui.(2018).High-frequency Oscillations in the Atmosphere above a Sunspot Umbra.ASTROPHYSICAL JOURNAL LETTERS,856(1),8. |
| MLA | Wang, Feng,et al."High-frequency Oscillations in the Atmosphere above a Sunspot Umbra".ASTROPHYSICAL JOURNAL LETTERS 856.1(2018):8. |
入库方式： OAI收割
来源：国家天文台
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