Spatial distribution of Kelvin-Helmholtz instability at low-latitude boundary layer under different solar wind speed conditions | |
Li, W. Y.; Guo, X. C.; Wang, C.; Li, WY (reprint author), Chinese Acad Sci, State Key Lab Space Weather, Ctr Space Sci & Appl Res, Beijing 100190, Peoples R China. | |
Department | 空间科学部 |
Source Publication | JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS |
2012 | |
Volume | 117Pages:A08230 |
ISSN | 0148-0227 |
Language | 英语 |
Abstract | Using the PPMLR-MHD global simulation model, we examined the Kelvin-Helmholtz (K-H) instability at the low-latitude boundary layer (LLBL) under northward interplanetary magnetic field (IMF) conditions with various solar wind speeds (400, 600, and 800 km/s). The spatial distribution of the K-H wave power in the equatorial plane shows two distinct power populations, referring to the two modes of K-H surface waves. The spatial evolution of K-H instability at the boundary layer is classified into four phases: quasi-stable, exponential growth, linear growth, and nonlinear phases. The boundary layer is quasi-stable near the subsolar point region. The K-H instability starts at about 30 degrees longitude, and grows exponentially with a spatial growth rate of 0.28 similar to 0.87 R-E(-1) until similar to 45 degrees longitude where the vortices fully develop. At larger longitudes, the instability grows linearly, while the vortices grow in size. From similar to 80 degrees longitude to the distant magnetotail, the K-H instability develops nonlinearly and the vortices roll up. The wave frequency, wavelength, and phase speed are given at various spatial points. Model results show that the higher solar wind speed generates K-H waves with higher frequency under the northward IMF, and the wavelengths and the phase speeds increase with the increase of the longitude. Moreover, we made a comparison of the K-H wave periods on Earth's, Mercury's and Saturn's magnetopauses by a proposed prediction method.; Using the PPMLR-MHD global simulation model, we examined the Kelvin-Helmholtz (K-H) instability at the low-latitude boundary layer (LLBL) under northward interplanetary magnetic field (IMF) conditions with various solar wind speeds (400, 600, and 800 km/s). The spatial distribution of the K-H wave power in the equatorial plane shows two distinct power populations, referring to the two modes of K-H surface waves. The spatial evolution of K-H instability at the boundary layer is classified into four phases: quasi-stable, exponential growth, linear growth, and nonlinear phases. The boundary layer is quasi-stable near the subsolar point region. The K-H instability starts at about 30 degrees longitude, and grows exponentially with a spatial growth rate of 0.28 similar to 0.87 R-E(-1) until similar to 45 degrees longitude where the vortices fully develop. At larger longitudes, the instability grows linearly, while the vortices grow in size. From similar to 80 degrees longitude to the distant magnetotail, the K-H instability develops nonlinearly and the vortices roll up. The wave frequency, wavelength, and phase speed are given at various spatial points. Model results show that the higher solar wind speed generates K-H waves with higher frequency under the northward IMF, and the wavelengths and the phase speeds increase with the increase of the longitude. Moreover, we made a comparison of the K-H wave periods on Earth's, Mercury's and Saturn's magnetopauses by a proposed prediction method. |
Indexed By | SCI |
Funding Project | 中国科学院空间科学与应用研究中心 |
Document Type | 期刊论文 |
Identifier | http://ir.nssc.ac.cn/handle/122/3220 |
Collection | 空间科学部 |
Corresponding Author | Li, WY (reprint author), Chinese Acad Sci, State Key Lab Space Weather, Ctr Space Sci & Appl Res, Beijing 100190, Peoples R China. |
Recommended Citation GB/T 7714 | Li, W. Y.,Guo, X. C.,Wang, C.,et al. Spatial distribution of Kelvin-Helmholtz instability at low-latitude boundary layer under different solar wind speed conditions[J]. JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,2012,117:A08230. |
APA | Li, W. Y.,Guo, X. C.,Wang, C.,&Li, WY .(2012).Spatial distribution of Kelvin-Helmholtz instability at low-latitude boundary layer under different solar wind speed conditions.JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS,117,A08230. |
MLA | Li, W. Y.,et al."Spatial distribution of Kelvin-Helmholtz instability at low-latitude boundary layer under different solar wind speed conditions".JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS 117(2012):A08230. |
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