Properties of Kelvin‐Helmholtz waves at the magnetopause under northward interplanetary magnetic field: Statistical study
Properties of Kelvin‐Helmholtz waves at the magnetopause under northward interplanetary magnetic field: Statistical study
复制标题
DOI：
10.1002/2014ja020379
复制
发表时间：
2014-09
期刊：
影响因子：
--
通讯作者：
D. Lin;Chi Wang;Wenya Li;B. Tang;Xiaocheng Guo;Zhong Peng
中科院分区：
文献类型：
--
作者：
D. Lin;Chi Wang;Wenya Li;B. Tang;Xiaocheng Guo;Zhong Peng
本文利用2008 - 2009年THEMIS探测器B和C的等离子体和磁场数据，寻找Kelvin-Helmholtz不稳定性的观测证据。在低纬边界层（LLBL）的行星际磁场（IMF）下，识别出14个具有卷起涡旋的KHI事件。我们收集了另外42个来自Geotail、双星星星TC-1和星团的观测报告，对KH波的性质进行了统计研究。所有56个卷起的KH波事件的定量特征的主导周期，相速度，和波长。进一步探讨了KH波周期与太阳风速度和IMF钟角的关系。结果表明，在较高的VSW下，KH周期趋于变短，而在较大的IMF钟角下，KH周期趋于变长。KH波长的空间分布表现出沿侧面磁层顶沿着距离日下点的纵向增长。统计结果为KH波的发展及其与行星际条件的联系提供了新的见解，加深了我们对磁层顶KHI的理解。
We search the plasma and magnetic field data of the Time History of Events and Macroscale Interactions during Substorms (THEMIS) probes B and C during 2008 and 2009 for observation evidences of the Kelvin‐Helmholtz instability (KHI). Fourteen KHI events with rolled‐up vortices are identified under the northward interplanetary magnetic field (IMF) at the low‐latitude boundary layer (LLBL). We collect another 42 events reported from the observations of the Geotail, Double Star TC‐1, and Cluster for a statistical study of the KH wave properties. All the 56 rolled‐up KH wave events are quantitatively characterized by the dominant period, phase velocity, and the wavelength. We further explore the relationship between the KH wave period and the solar wind velocity (VSW) and the IMF clock angle. It is found that the KH period tends to be shorter under a higher VSW, and longer with a larger IMF clock angle. The spatial distribution of the KH wavelength shows a longitudinal growth with increasing distance from the subsolar point along the flank magnetopause. The statistical results provide new insights for the development of KH waves and their connection with the interplanetary conditions and deepen our understanding of the KHI at the magnetopause.