Nonlinear alfvénic fluctuations in uniform magnetic background fields
作者:
E. Weisshaar,
期刊:
Geophysical & Astrophysical Fluid Dynamics
(Taylor Available online 1988)
卷期:
Volume 41,
issue 1-2
页码: 141-170
ISSN:0309-1929
年代: 1988
DOI:10.1080/03091928808208834
出版商: Taylor & Francis Group
关键词: Magnetic fields;turbulence
数据来源: Taylor
摘要:
The two dimensional incompressible MHD equations describing the decay of a random initial velocity field in the presence of a uniform magnetic background field are solved numerically by a Chebyshev spectral method. The nonlinear interactions of standing Alfvén-waves of a given energy are studied for various Reynolds numbers and field strengths of the magnetic background field. Small scale structures are generated by these interactions, which increase the energy dissipation, however, the uniform background field suppresses the production of arbitrary small scales. Thus energy dissipation is found to be insignificant at sufficiently high Reynolds numbers. Anisotropies of the fluctuating field components are also studied. In the temporal evolution they appear first in the magnetic field. This is explained by the conservation of mean square vector potential in the limit of infinite conductivity.
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