Solar Kinetic Energy and Cross Helicity Spectra

doi:10.3847/2041-8213/aad337

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	Solar Kinetic Energy and Cross Helicity Spectra
	Zhang, Hongqi 1; Brandenburg, Axel 2,3,4,5,6,7
刊名	ASTROPHYSICAL JOURNAL LETTERS
	2018-08-01
卷号	862 期号:2 页码:5
关键词	dynamo Sun: activity Sun: magnetic fields Sun: photosphere
ISSN号	2041-8205
DOI	10.3847/2041-8213/aad337
英文摘要	We develop a formalism that treats the calculation of solar kinetic energy and cross helicity spectra in an equal manner to that of magnetic energy and helicity spectra. The magnetic helicity spectrum is shown to be equal to the vertical part of the current helicity spectrum divided by the square of the wavenumber. For the cross helicity, we apply the recently developed two-scale approach globally over an entire active region to account for the sign change between the two polarities. Using vector magnetograms and Dopplergrams of NOAA. 11158 and 12266, we show that kinetic and magnetic energy spectra have similar slopes at intermediate wavenumbers, where the contribution from the granulation velocity has been removed. At wavenumbers around 0.3 Mm(-1), the magnetic helicity is found to be close to its maximal value. The cross helicity spectra are found to be within about 10% of the maximum possible value. Using the two-scale method for NOAA. 12266, the global cross helicity spectrum is found to be particularly steep, similarly to what has previously been found in theoretical models of spot generation. In the quiet Sun, by comparison, the cross helicity spectrum is found to be small.
资助项目	National Natural Science Foundation (NNSF) of China[11673033] ; National Natural Science Foundation (NNSF) of China[11427803] ; National Natural Science Foundation (NNSF) of China[11427901] ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; NSF Astronomy and Astrophysics Grants Program[1615100] ; University of Colorado
WOS关键词	TURBULENCE
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000440583700003
资助机构	National Natural Science Foundation (NNSF) of China ; National Natural Science Foundation (NNSF) of China ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; NSF Astronomy and Astrophysics Grants Program ; NSF Astronomy and Astrophysics Grants Program ; University of Colorado ; University of Colorado ; National Natural Science Foundation (NNSF) of China ; National Natural Science Foundation (NNSF) of China ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; NSF Astronomy and Astrophysics Grants Program ; NSF Astronomy and Astrophysics Grants Program ; University of Colorado ; University of Colorado ; National Natural Science Foundation (NNSF) of China ; National Natural Science Foundation (NNSF) of China ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; NSF Astronomy and Astrophysics Grants Program ; NSF Astronomy and Astrophysics Grants Program ; University of Colorado ; University of Colorado ; National Natural Science Foundation (NNSF) of China ; National Natural Science Foundation (NNSF) of China ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; Huairou Solar Observing Station of National Astronomical Observatories, Chinese Academy of Sciences ; NSF Astronomy and Astrophysics Grants Program ; NSF Astronomy and Astrophysics Grants Program ; University of Colorado ; University of Colorado
内容类型	期刊论文
源URL	[http://ir.bao.ac.cn/handle/114a11/22277]
专题	中国科学院国家天文台
通讯作者	Zhang, Hongqi
作者单位	1.Chinese Acad Sci, Key Lab Solar Act, Natl Astron Observ, Beijing 100012, Peoples R China 2.KTH Royal Inst Technol, NORDITA, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden 3.Stockholm Univ, Roslagstullsbacken 23, SE-10691 Stockholm, Sweden 4.Univ Colorado, JILA, Boulder, CO 80303 USA 5.Univ Colorado, Dept Astrophys & Planetary Sci, Boulder, CO 80303 USA 6.Stockholm Univ, AlbaNova Univ Ctr, Dept Astron, SE-10691 Stockholm, Sweden 7.Univ Colorado, Lab Atmospher & Space Phys, Boulder, CO 80303 USA
推荐引用方式 GB/T 7714	Zhang, Hongqi,Brandenburg, Axel. Solar Kinetic Energy and Cross Helicity Spectra[J]. ASTROPHYSICAL JOURNAL LETTERS,2018,862(2):5.
APA	Zhang, Hongqi,&Brandenburg, Axel.(2018).Solar Kinetic Energy and Cross Helicity Spectra.ASTROPHYSICAL JOURNAL LETTERS,862(2),5.
MLA	Zhang, Hongqi,et al."Solar Kinetic Energy and Cross Helicity Spectra".ASTROPHYSICAL JOURNAL LETTERS 862.2(2018):5.