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Ion-Scale Kinetic Alfven Turbulence: MMS Measurements of the Alfven Ratio in the Magnetosheath
Roberts, O. W.1; Toledo-Redondo, S.2; Perrone, D.3; Zhao, J.4; Narita, Y.5; Gershman, D.6; Nakamura, R.5; Lavraud, B.7; Escoubet, C. P.1; Giles, B.6
刊名GEOPHYSICAL RESEARCH LETTERS
2018-08-28
卷号45期号:16页码:7974-7984
关键词turbulence magnetosheath plasmas
ISSN号0094-8276
DOI10.1029/2018GL078498
英文摘要

Turbulence in the Earth's magnetosheath at ion kinetic scales is investigated with the magnetospheric multiscale spacecraft. Several possibilities in the wave paradigm have been invoked to explain plasma turbulence at ion kinetic scales such as kinetic Alfven, slow, or magnetosonic waves. To differentiate between these different plasma waves is a challenging task, especially since some waves, in particular, kinetic slow waves and kinetic Alfven waves, share some properties making the possibility to distinguishing between them very difficult. Using the excellent time resolution data set provided from both the fluxgate magnetometer and the Fast Plasma Instrument, the ratio of trace velocity fluctuations to the magnetic fluctuations (in Alfven units), which is termed the Alfven ratio, can be calculated down to ion kinetic scales. Comparison of the measured Alfven ratio is performed with respect to the expectation from two-fluid magnetohydrodynamic theory for the kinetic slow wave and kinetic Alfven wave. Moreover, the plasma data also allow normalized fluctuation amplitudes of density and magnetic field to be compared differentiating between magnetosonic-like and kinetic Alfven-like turbulence. Using these two different ratios, we can rule out that the fluctuations at ion scales are dominated by magnetosonic-like fluctuations or kinetic slow-like fluctuations and show that they are consistent with kinetic Alfven-like fluctuations. This suggests that in the wave paradigm, heating in the direction of the parallel magnetic field is predominantly by the Landau damping of the kinetic Alfven wave.

WOS关键词SOLAR-WIND TURBULENCE ; LOW-FREQUENCY WAVES ; MAGNETOHYDRODYNAMIC TURBULENCE ; MAGNETOSPHERIC MULTISCALE ; FLUCTUATION SPECTRUM ; DENSITY ; PLASMA ; MHD ; ANISOTROPY ; AU
WOS研究方向Geology
语种英语
出版者AMER GEOPHYSICAL UNION
WOS记录号WOS:000445612500011
内容类型期刊论文
源URL[http://libir.pmo.ac.cn/handle/332002/21286]  
专题中国科学院紫金山天文台
通讯作者Roberts, O. W.
作者单位1.European Space Agcy, ESA ESTEC, Noordwijk, Netherlands
2.European Space Agcy, ESA ESAC, Madrid, Spain
3.Imperial Coll London, Dept Phys, London, England
4.Chinese Acad Sci, Key Lab Planetary Sci, Purple Mt Observ, Nanjing, Jiangsu, Peoples R China
5.Austrian Acad Sci, Space Res Inst, Graz, Austria
6.NASA, Goddard Space Flight Ctr, Greenbelt, MD USA
7.Univ Toulouse, Inst Rech Astrophys & Planetol, CNRS, UPS,CNES, Toulouse, France
8.Southwest Res Inst, San Antonio, TX USA
推荐引用方式
GB/T 7714
Roberts, O. W.,Toledo-Redondo, S.,Perrone, D.,et al. Ion-Scale Kinetic Alfven Turbulence: MMS Measurements of the Alfven Ratio in the Magnetosheath[J]. GEOPHYSICAL RESEARCH LETTERS,2018,45(16):7974-7984.
APA Roberts, O. W..,Toledo-Redondo, S..,Perrone, D..,Zhao, J..,Narita, Y..,...&Burch, J..(2018).Ion-Scale Kinetic Alfven Turbulence: MMS Measurements of the Alfven Ratio in the Magnetosheath.GEOPHYSICAL RESEARCH LETTERS,45(16),7974-7984.
MLA Roberts, O. W.,et al."Ion-Scale Kinetic Alfven Turbulence: MMS Measurements of the Alfven Ratio in the Magnetosheath".GEOPHYSICAL RESEARCH LETTERS 45.16(2018):7974-7984.
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