The rotational quenching of the rotation-induced kinetic alpha-effect
作者:
V.V. Pipin,
G. Rüdiger,
L.L. Kitchatinov,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 1996)
卷期:
Volume 83,
issue 1-2
页码: 119-133
ISSN:0309-1929
年代: 1996
DOI:10.1080/03091929608213644
出版商: Taylor & Francis Group
关键词: Turbulence;global rotation;stratification;large-scale vortices;galaxies;accretion disks
数据来源: Taylor
摘要:
A theory of the non-diffusive anisotropic kinetic alpha-effect (“Γ-effect”) for densitystratified rotating turbulent fluids is developed. No limitations on the rotation rate are imposed and the fully nonlinear dependence of the Γ-effect on the angular velocity is studied. When the Coriolis number, ω* = 2τ ω, is small the dimensionless “dynamo number”, Cτ, characterising the power of the Γ-effect, grows with ω*. The dependence, however, reaches a maximum for ω* ∼ 2. For still higher rotation rates CΛdecreases as 1/ω*. In opposition, the corresponding number, Cx, of the hydromagnetic α2-dynamo problems remains finite for very large ω*. Hence, for fast rotation the hydrodynamic Γ-effect is small while the hydromagnetic α-effect remains large. In consequence, the large-scale magnetic and velocity structures are expected to be generated with roughly equal power in slowly rotating objects. In the rapid rotators, however, generation of the large-scale flows is problematic.
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