Radial Variations of Outward and Inward Alfvenic Fluctuations Based on Ulysses Observations

doi:10.3847/1538-4357/aa9615

	Radial Variations of Outward and Inward Alfvenic Fluctuations Based on Ulysses Observations
	Yang, L.1,2 ; Lee, L. C.3,4; Li, J. P.5; Luo, Q. Y.1; Kuo, C. L.6; Shi, J. K.2; Wu, D. J.1
刊名	ASTROPHYSICAL JOURNAL
	2017-12-01
卷号	850 期号:2 页码:11
关键词	magnetohydrodynamics (MHD) methods: analytical plasmas solar wind waves
ISSN号	0004-637X
DOI	10.3847/1538-4357/aa9615
通讯作者	Yang, L.(ylei@pmo.ac.cn)
英文摘要	Ulysses magnetic and plasma data are used to study hourly scale Alfvenic fluctuations in the solar polar wind. The calculated energy ratio R-vA(2) (cal) of inward to outward Alfven waves is obtained from the observed Walen slope through an analytical expression, and the observed R-vA(2) (obs) is based on a direct decomposition of original Alfvenic fluctuations into outward-and inward-propagating Alfven waves. The radial variation of R-vA(2) (cal) shows a monotonically increasing trend with heliocentric distance r, implying the increasing local generation or contribution of inward Alfven waves. The contribution is also shown by the radial increase in the occurrence of dominant inward fluctuations. We further pointed out a higher occurrence (similar to 83% of a day in average) of dominant outward Alfvenic fluctuations in the solar wind than previously estimated. Since R-vA(2) (cal) is more accurate than R-vA(2) (obs) in the measurement of the energy ratio for dominant outward fluctuations, the values of R-vA(2) (cal) in our results are likely more realistic in the solar wind than those previously estimated as well as R-vA(2) (obs) in our results. The duration ratio R-T of dominant inward to all Alfvenic fluctuations increases monotonically with r, and is about two or more times that from Voyager 2 observations at r >= 4 au. These results reveal new qualitative and quantitative features of Alfvenic fluctuations therein compared with previous studies and put constraints on modeling the variation of solar wind fluctuations.
WOS关键词	HIGH HELIOGRAPHIC LATITUDES ; SOLAR-WIND FLUCTUATIONS ; MAGNETOHYDRODYNAMIC TURBULENCE ; MHD TURBULENCE ; CROSS-HELICITY ; HYDROMAGNETIC TURBULENCE ; STATISTICAL PROPERTIES ; INTERPLANETARY MEDIUM ; INNER HELIOSPHERE ; RESIDUAL ENERGY
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000425474700001
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/22283]
专题	中国科学院紫金山天文台
通讯作者	Yang, L.
作者单位	1.Chinese Acad Sci, Purple Mt Observ, Key Lab Planetary Sci, Nanjing 210008, Jiangsu, Peoples R China 2.Chinese Acad Sci, Natl Space Sci Ctr, State Key Lab Space Weather, Beijing 100190, Peoples R China 3.Macau Univ Sci & Technol, Space Sci Inst, Macau, Peoples R China 4.Acad Sinica, Inst Earth Sci, Taipei 11529, Taiwan 5.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Jiangsu, Peoples R China 6.Natl Cent Univ, Inst Space Sci, Jhongli 320, Taiwan
推荐引用方式 GB/T 7714	Yang, L.,Lee, L. C.,Li, J. P.,et al. Radial Variations of Outward and Inward Alfvenic Fluctuations Based on Ulysses Observations[J]. ASTROPHYSICAL JOURNAL,2017,850(2):11.
APA	Yang, L..,Lee, L. C..,Li, J. P..,Luo, Q. Y..,Kuo, C. L..,...&Wu, D. J..(2017).Radial Variations of Outward and Inward Alfvenic Fluctuations Based on Ulysses Observations.ASTROPHYSICAL JOURNAL,850(2),11.
MLA	Yang, L.,et al."Radial Variations of Outward and Inward Alfvenic Fluctuations Based on Ulysses Observations".ASTROPHYSICAL JOURNAL 850.2(2017):11.