DOI: 10.1029/2018JA025552
Scopus记录号: 2-s2.0-85052625856
论文题名: Kelvin-Helmholtz Instability in the Geotail Low-Latitude Boundary Layer
作者: Leonovich A.S. ; Kozlov D.A.
刊名: Journal of Geophysical Research: Space Physics
ISSN: 21699380
出版年: 2018
卷: 123, 期: 8 起始页码: 6548
结束页码: 6561
语种: 英语
英文关键词: geotail
; K-H instability
; LLB
; magnetosphere
; MHD oscillations
英文摘要: The low-latitude boundary layer stability problem in the geotail is solved numerically. This study relies on a cylindrical model of the geotail, with a smooth boundary, enwrapped by a helical solar wind flow. It is shown that three types of unstable magnetohydrodynamic waves exist in this plasma system: (1) surface waves at the magnetopause, (2) waves radiated into the solar wind, and (3) eigenmodes of the waveguide within the geotail. Unstable surface waves generated in the low- to medium-speed solar wind have the largest growth rate. They are driven in the Pc3–Pc6 geomagnetic pulsation range and have a local maximum at Pc4 frequencies. In the cylindrical model in question the minimum transverse wavelengths of the unstable oscillations are much less than the shear layer thickness. This differentiates it from models with Cartesian geometry, where the minimum transverse wavelengths of unstable oscillations are larger than the boundary layer thickness. In high-speed solar wind flows the magnetopause is stable to surface waves but unstable to radiative modes. The growth rate of such oscillations is an order of magnitude smaller than that for surface waves generated in the low- to medium-speed solar wind. If the helicity of high-speed solar wind flows enwrapping the magnetosphere is small, the oscillations are unstable in the Pc4–Pc6 geomagnetic pulsation range, with their maximum growth rate being in the Pc5 range. If the helicity of high-speed solar wind flow enwrapping the magnetosphere is large enough, the oscillations are unstable throughout the Pc1–Pc6 geomagnetic pulsation range. ©2018. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/113335
Appears in Collections: 气候减缓与适应
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作者单位: Institute of Solar-Terrestrial Physics, SB RAS, Irkutsk, Russian Federation
Recommended Citation:
Leonovich A.S.,Kozlov D.A.. Kelvin-Helmholtz Instability in the Geotail Low-Latitude Boundary Layer[J]. Journal of Geophysical Research: Space Physics,2018-01-01,123(8)