Composition of Wave Modes in Magnetosheath Turbulence from Sub-ion to Sub-electron Scales

doi:10.3847/1538-4357/ab1be7

	Composition of Wave Modes in Magnetosheath Turbulence from Sub-ion to Sub-electron Scales
	Zhu, Xingyu 1; He, Jiansen 1; Verscharen, Daniel 2,3; Zhao, Jinsong4
刊名	ASTROPHYSICAL JOURNAL
	2019-06-10
卷号	878 期号:1 页码:10
关键词	turbulence waves
ISSN号	0004-637X
DOI	10.3847/1538-4357/ab1be7
通讯作者	Zhao, Jinsong(jshept@pku.edu.cn)
英文摘要	The nature of plasma turbulence remains unclear at kinetic scales, especially sub-electron scales. We simultaneously investigate spectra of magnetic and electric fields from proton scales (similar to 1 Hz) down to sub-electron scales (similar to 1 kHz) using MMS measurements in the magnetosheath turbulence. We find that magnetic field spectra exhibit identical behavior between ion and electron scales, while they bifurcate at about 30 Hz (around electron inertial scale) and then aggregate around 1 kHz (around electron gyrofrequency). Kinetic Alfven waves (KAWs) are identified in the range from 1 to 30 Hz: (1) the power spectral indices of PSD(B) and PSD(E) are about -3 and -1; (2) parallel magnetic and electric fluctuations are present but subdominant. Magnetic field spectra obtained from postnoon region events show a clear spectral enhancement, which is identified as quasi-parallel whistler waves (WWs). Electric field spectra present a wide bulge around 800 Hz, which is also seen as island-like patterns in the time-period wavelet spectra. The electric field spectral enhancement is dominated by field-parallel fluctuations and is, therefore, diagnosed as ion acoustic waves (IAWs). We also perform a quantitative analysis of the multiple mode types using polarization predictions from two-fluid theory. We obtain the energy partition of electromagnetic fields for different wave modes and successfully reproduce the observed PSDs of B-perpendicular to, B-parallel to, E-perpendicular to, and E-parallel to. Our findings suggest that the magnetosheath turbulence consists of a mixture of multiple wave modes (KAW, WW, and IAW) in the range from sub-ion scales to sub-electron scales.
WOS关键词	SOLAR-WIND ; SEPARATRIX REGIONS ; DISPERSION ; SPECTRA ; MHD
WOS研究方向	Astronomy & Astrophysics
语种	英语
出版者	IOP PUBLISHING LTD
WOS记录号	WOS:000471316800011
内容类型	期刊论文
源URL	[http://libir.pmo.ac.cn/handle/332002/27495]
专题	中国科学院紫金山天文台
通讯作者	Zhao, Jinsong
作者单位	1.Peking Univ, Sch Earth & Space Sci, Beijing 100871, Peoples R China 2.Univ Coll London, Mullard Space Sci Lab, Dorking RH5 6NT, Surrey, England 3.Univ New Hampshire, Space Sci Ctr, Durham, NH 03824 USA 4.Chinese Acad Sci, Purple Mt Observ, Nanjing 210008, Jiangsu, Peoples R China
推荐引用方式 GB/T 7714	Zhu, Xingyu,He, Jiansen,Verscharen, Daniel,et al. Composition of Wave Modes in Magnetosheath Turbulence from Sub-ion to Sub-electron Scales[J]. ASTROPHYSICAL JOURNAL,2019,878(1):10.
APA	Zhu, Xingyu,He, Jiansen,Verscharen, Daniel,&Zhao, Jinsong.(2019).Composition of Wave Modes in Magnetosheath Turbulence from Sub-ion to Sub-electron Scales.ASTROPHYSICAL JOURNAL,878(1),10.
MLA	Zhu, Xingyu,et al."Composition of Wave Modes in Magnetosheath Turbulence from Sub-ion to Sub-electron Scales".ASTROPHYSICAL JOURNAL 878.1(2019):10.