科研之友
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摘要
It is shown that thermal turbulence, not unlike the standard kinetic and magnetic turbulence, can be an effective driver of a mean-field dynamo. In simple models, such as hydrodynamics and magneto-hydrodynamics, both vorticity and induction equations can have strong thermal drives that resemble the alpha and gamma effects in conventional dynamo theories; the thermal drives are likely to be dominant in systems that are endowed with subsonic, low-beta turbulence. A pure thermal dynamo is quite different from the conventional dynamo in which the same kinetic/magnetic mix in the ambient turbulence can yield a different ratio of macroscopic magnetic/vortical fields. The possible implications of the similarities and differences between the thermal and non-thermal dynamos are discussed. The thermal dynamo is shown to be highly important in the stellar and planetary context, and yields results broadly consistent with other theoretical and experimental approaches. Published by AIP Publishing.
- 出版日期2016-5
