A multi-layered kinematic dynamo model: implications of a stratified upper layer in the Earth's core

	A multi-layered kinematic dynamo model: implications of a stratified upper layer in the Earth's core
	Liao, X; Zhang, K ; Gubbins, D
刊名	GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS
	2005-10-01
卷号	99 期号:5 页码:377-395
关键词	geodynamo stable layer shear flow
英文摘要	It has been suggested that there exists a stably stratified electrically conducting layer at the top of the Earth's outer fluid core and that lateral temperature gradients in the lower mantle is capable of a driving thermal-wind-type flow near the core-mantle boundary. We investigate how such a flow in a stable layer could influence the geomagnetic field and the geodynamo using a very simple two-dimensional kinematic dynamo model in Cartesian geometry. The dynamo has four layers representing the inner core, convecting lower outer core, stable upper core, and insulating mantle. An alpha(2) dynamo operates in the convecting outer core and a horizontal shear flow is imposed in the stable layer. Exact dynamo solutions are obtained for a range of parameters, including different conductivities for the stable layer and inner core. This allows us to connect our solutions with known, simpler solutions of a single-layer alpha(2) dynamo, and thereby assess the effects of the extra layers. We confirm earlier results that a stable, static layer can enhance dynamo action. We find that shear flows produce dynamo wave solutions with a different spatial structure from the steady alpha(2) dynamos solutions. The stable layer controls the behavior of the dynamo system through the interface conditions, providing a new means whereby lateral variations on the boundary can influence the geomagnetic field.
WOS标题词	Science & Technology ; Physical Sciences ; Technology
类目[WOS]	Astronomy & Astrophysics ; Geochemistry & Geophysics ; Mechanics
研究领域[WOS]	Astronomy & Astrophysics ; Geochemistry & Geophysics ; Mechanics
关键词[WOS]	CONVECTION ; BOUNDARY ; OCEAN ; FLOW
收录类别	SCI
语种	英语
WOS记录号	WOS:000233809100002
公开日期	2010-07-30
内容类型	期刊论文
源URL	[http://119.78.226.72//handle/331011/10490]
专题	上海天文台_天文地球动力学研究中心
作者单位	1.Chinese Acad Sci, Shanghai Astron Obsev, Shanghai 200030, Peoples R China 2.Univ Exeter, Dept Math Sci, Exeter EX4 4QE, Devon, England 3.Univ Leeds, Sch Earth Sci, Leeds LS2 9JT, W Yorkshire, England
推荐引用方式 GB/T 7714	Liao, X,Zhang, K,Gubbins, D. A multi-layered kinematic dynamo model: implications of a stratified upper layer in the Earth's core[J]. GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS,2005,99(5):377-395.
APA	Liao, X,Zhang, K,&Gubbins, D.(2005).A multi-layered kinematic dynamo model: implications of a stratified upper layer in the Earth's core.GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS,99(5),377-395.
MLA	Liao, X,et al."A multi-layered kinematic dynamo model: implications of a stratified upper layer in the Earth's core".GEOPHYSICAL AND ASTROPHYSICAL FLUID DYNAMICS 99.5(2005):377-395.