Observations of white-light flares in NOAA active region 11515: high occurrence rate and relationship with magnetic transients

doi:10.1051/0004-6361/201731817

CORC > 国家天文台 > 中国科学院国家天文台

	Observations of white-light flares in NOAA active region 11515: high occurrence rate and relationship with magnetic transients
	Song, Y. L.1,2; Tian, H.1; Zhang, M.3,4; Ding, M. D.5
刊名	ASTRONOMY & ASTROPHYSICS
	2018-06-01
卷号	613 页码:8
关键词	Sun: activity Sun: magnetic fields Sun: flares Sun: photosphere Sun: chromosphere
ISSN号	1432-0746
DOI	10.1051/0004-6361/201731817
英文摘要	Aims. There are two goals in this study. One is to investigate how frequently white-light flares (WLFs) occur in a flare-productive active region (NOAA active region 11515). The other is to investigate the relationship between WLFs and magnetic transients (MTs). Methods. We used the high-cadence (45 s) full-disk continuum filtergrams and line-of-sight magnetograms taken by the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO) to identify WLFs and MTs, respectively. Images taken by the Atmospheric Imaging Assembly (AIA) on board SDO were also used to show the flare morphology in the upper atmosphere. Results. We found at least 20 WLFs out of a total of 70 flares above C class (28.6%) in NOAA active region 11515 during its passage across the solar disk (E45 degrees -W45 degrees). Each of these WLFs occurred in a small region, with a short duration of about 5 min. The enhancement of the white-light continuum intensity is usually small, with an average enhancement of 8.1%. The 20 WLFs we observed were found along an unusual configuration of the magnetic field that was characterized by a narrow ribbon of negative field. Furthermore, the WLFs were found to be accompanied by MTs, with radical changes in magnetic field strength (or even a sign reversal) observed during the flare. In contrast, there is no obvious signature of MTs in the 50 flares without white-light enhancements. Conclusions. Our results suggest that WLFs occur much more frequently than previously thought, with most WLFs being fairly weak enhancements. This may explain why WLFs are reported rarely. Our observations also suggest that MTs and WLFs are closely related and appear cospatial and cotemporal, when considering HMI data. A greater enhancement of WL emission is often accompanied by a greater change in the line-of-sight component of the unsigned magnetic field. Considering the close relationship between MTs and WLFs, many previously reported flares with MTs may be WLFs.
资助项目	NSFC[41574166] ; NSFC[11125314] ; NSFC[11733003] ; Recruitment Program of Global Experts of China ; Specialized Research Fund for State Key Laboratories ; Max Planck Partner Group program ; ISSI ; ISSI-BJ
WOS关键词	SOLAR-FLARES ; X-RAY ; CHROMOSPHERIC CONDENSATION ; CONTINUUM EMISSION ; ALFVEN WAVES ; G-BAND ; ATMOSPHERE ; YOHKOH ; ENERGY ; LINE
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	EDP SCIENCES S A
WOS记录号	WOS:000433880500001
资助机构	NSFC ; NSFC ; Recruitment Program of Global Experts of China ; Recruitment Program of Global Experts of China ; Specialized Research Fund for State Key Laboratories ; Specialized Research Fund for State Key Laboratories ; Max Planck Partner Group program ; Max Planck Partner Group program ; ISSI ; ISSI ; ISSI-BJ ; ISSI-BJ ; NSFC ; NSFC ; Recruitment Program of Global Experts of China ; Recruitment Program of Global Experts of China ; Specialized Research Fund for State Key Laboratories ; Specialized Research Fund for State Key Laboratories ; Max Planck Partner Group program ; Max Planck Partner Group program ; ISSI ; ISSI ; ISSI-BJ ; ISSI-BJ ; NSFC ; NSFC ; Recruitment Program of Global Experts of China ; Recruitment Program of Global Experts of China ; Specialized Research Fund for State Key Laboratories ; Specialized Research Fund for State Key Laboratories ; Max Planck Partner Group program ; Max Planck Partner Group program ; ISSI ; ISSI ; ISSI-BJ ; ISSI-BJ ; NSFC ; NSFC ; Recruitment Program of Global Experts of China ; Recruitment Program of Global Experts of China ; Specialized Research Fund for State Key Laboratories ; Specialized Research Fund for State Key Laboratories ; Max Planck Partner Group program ; Max Planck Partner Group program ; ISSI ; ISSI ; ISSI-BJ ; ISSI-BJ
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/21717]
专题	中国科学院国家天文台
通讯作者	Tian, H.
作者单位	1.Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China 2.Chinese Acad Sci, State Key Lab Space Weather, Beijing 100190, Peoples R China 3.Chinese Acad Sci, Natl Astron Observ, Key Lab Solar Act, Beijing 100012, Peoples R China 4.Univ Chinese Acad Sci, Sch Astron & Space Sci, Beijing 100049, Peoples R China 5.Nanjing Univ, Sch Astron & Space Sci, Nanjing 210093, Jiangsu, Peoples R China
推荐引用方式 GB/T 7714	Song, Y. L.,Tian, H.,Zhang, M.,et al. Observations of white-light flares in NOAA active region 11515: high occurrence rate and relationship with magnetic transients[J]. ASTRONOMY & ASTROPHYSICS,2018,613:8.
APA	Song, Y. L.,Tian, H.,Zhang, M.,&Ding, M. D..(2018).Observations of white-light flares in NOAA active region 11515: high occurrence rate and relationship with magnetic transients.ASTRONOMY & ASTROPHYSICS,613,8.
MLA	Song, Y. L.,et al."Observations of white-light flares in NOAA active region 11515: high occurrence rate and relationship with magnetic transients".ASTRONOMY & ASTROPHYSICS 613(2018):8.