Observations of turbulence in a Kelvin‐Helmholtz event on 8 September 2015 by the Magnetospheric Multiscale mission
Observations of turbulence in a Kelvin‐Helmholtz event on 8 September 2015 by the Magnetospheric Multiscale mission
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磁层多尺度任务对 2015 年 9 月 8 日开尔文-亥姆霍兹事件中湍流的观测
DOI：
10.1002/2016ja023458
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发表时间：
2016
期刊：
影响因子：
--
通讯作者：
A. Sturner
中科院分区：
文献类型：
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作者：
J. Stawarz;S. Eriksson;F. Wilder;R. Ergun;Steven J. Schwartz;A. Pouquet;J. Burch;B. Giles;Y. Khotyaintsev;O. Contel;P. Lindqvist;W. Magnes;C. Pollock;C. Russell;R. Strangeway;R. Torbert;L. Avanov;J. Dorelli;J. Eastwood;D. Gershman;K. Goodrich;David M. Malaspina;G. Marklund;L. Mirioni;A. Sturner
使用来自磁层多尺度任务的数据，对等离子体湍流中的速度、磁场和三维电场的空间和高时间分辨率特性进行了观测。对地球磁层顶上的开尔文-亥姆霍兹不稳定性(KHI)的观测结果进行了分析，这既提供了一系列可重复的间隔进行分析，提供了更好的统计数据，也提供了对KHI中湍流特性的初步了解。第一次检查了高频离子和电子速度谱的直接观测，显示了在动力学尺度上不同的离子和电子行为。时间谱表现出随离子回旋频率和低杂化频率附近斜率的变化而变化的幂规律行为。这项工作首次提供了与KHI相关的准二维湍流一致的湍流间歇性和各向异性的观测证据。动力学尺度的间歇行为被发现与以前对太阳风湍流的研究有所不同，这导致了对KHI中湍流动力学的新见解。
Spatial and high‐time‐resolution properties of the velocities, magnetic field, and 3‐D electric field within plasma turbulence are examined observationally using data from the Magnetospheric Multiscale mission. Observations from a Kelvin‐Helmholtz instability (KHI) on the Earth's magnetopause are examined, which both provides a series of repeatable intervals to analyze, giving better statistics, and provides a first look at the properties of turbulence in the KHI. For the first time direct observations of both the high‐frequency ion and electron velocity spectra are examined, showing differing ion and electron behavior at kinetic scales. Temporal spectra exhibit power law behavior with changes in slope near the ion gyrofrequency and lower hybrid frequency. The work provides the first observational evidence for turbulent intermittency and anisotropy consistent with quasi two‐dimensional turbulence in association with the KHI. The behavior of kinetic‐scale intermittency is found to have differences from previous studies of solar wind turbulence, leading to novel insights on the turbulent dynamics in the KHI.