The onset of magnetoconvection at large Prandtl number in a rotating layer I. Finite magnetic diffusion
作者:
P.H. Roberts,
C.A. Jones,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 2000)
卷期:
Volume 92,
issue 3-4
页码: 289-325
ISSN:0309-1929
年代: 2000
DOI:10.1080/03091920008203719
出版商: Taylor & Francis Group
关键词: Magnetohydrodynamics;Rotating fluids;Convection;Dynamo theory;Earth's core
数据来源: Taylor
摘要:
This paper develops further a convection model that has been studied several times previously as a very crude idealization of planetary core dynamics. A plane layer of electrically-conducting fluid rotates about the vertical in the presence of a magnetic field. Such a field can be created spontaneously, as in the Childress—Soward dynamo, but here it is uniform, horizontal and externally-applied. The Prandtl number of the fluid is large, but the Ekman, Elsasser and Rayleigh numbers are of order unity, as is the ratio of thermal to magnetic diffusivity. Attention is focused on the onset of convection as the temperature difference applied across the layer is increased, and on the preferred mode,i.e., the planform and time-dependence of small amplitude convection. The case of main interest is the layer confined between electrically-insulating no-slip walls, but the analysis is guided by a parallel study based on illustrative boundary conditions that are mathematically simpler.
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