The role of the Yoshizawa effect in the Archontis dynamo
The role of the Yoshizawa effect in the Archontis dynamo
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吉泽效应在 Archontis 发电机中的作用
DOI：
10.1111/j.1365-2966.2009.15254.x
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发表时间：
2009
影响因子：
4.8
通讯作者：
A. Brandenburg
中科院分区：
文献类型：
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作者：
S. Sur;A. Brandenburg
研究了简单非螺旋流的平均磁场的产生，其中任一符号的净交叉螺旋度都可能出现。这种流是称为Archontis流的LSO，是Arnold-Beltrami-Chilresse流的推广，但省略了余弦项。交叉螺旋度的存在导致了被称为吉泽效应的平均场发电机效应。对这种流动的直接数值模拟表明，在比流动规模更大的尺度上存在磁场。与早先的预期相反，吉泽效应被发现与平均磁场成正比，因此当磁雷诺数超过某一临界值时，吉泽效应可以导致其指数而不是线性放大。与α效应发电机不同的是，我们发现吉泽效应不受守恒定律的明显约束。认为这是由于动量方程中强迫项的存在，导致了与磁场的非零关联。最后讨论了太阳风湍流在能量辐合中的应用。
The generation of mean magnetic fields is studied for a simple non-helical flow where a net cross helicity of either sign can emerge. This flow, which is a lso known as the Archontis flow, is a generalization of the Arnold‐Beltrami‐Childress flow, but with the cosine terms omitted. The presence of cross helicity leads to a mean-field dynamo effect that is known as the Yoshizawa effect. Direct numerical simulations of such flows demonstrate the presence of magnetic fields on scales larger than the scale of the flow. Con trary to earlier expectations, the Yoshizawa effect is found to be proportional to the mean magnetic field and can therefore lead to its exponential instead of just linear amplification for magnetic Reynolds numbers that exceed a certain critical value. Unlike α effect dynamos, it is found that the Yoshizawa effect is not noticeably constrained by the presence of a conservat ion law. It is argued that this is due to the presence of a forcing term in the momentum equation which leads to a nonzero correlation with the magnetic field. Finally, the applicati on to energy convergence in solar wind turbulence is discussed.
DOI：
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发表时间：
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期刊：
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影响因子：
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作者：
M. Schrinner;K. R. Adler;D. Schmitt;M. Rheinhardt;U. Christensen
通讯作者：
M. Schrinner;K. R. Adler;D. Schmitt;M. Rheinhardt;U. Christensen
地球发电机模拟的数值方法
DOI：
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发表时间：
2007
期刊：
影响因子：
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作者：
Masaki Yoshida;Akira Kageyama;陰山 聡(招待講演);陰山聡;陰山 聡(招待講演);陰山聡;Akira Kageyama (Invited Talk);陰山 聡(招待講演);陰山聡;Akira Kageyama (Invited Talk);陰山 聡(招待講演);陰山聡;陰山 聡(招待講演);N.Ohno;大野 暢亮;M.Furuichi;Akira Kageyama (Invited talk);Akira Kageyama;陰山聡(招待講演);陰山聡(招待講演);Akira Kageyama (Invited talk);Akira Kageyama (Invited talk);Akira Kageyama;Akira Kageyama;宮腰 剛広;宮腰 剛広;陰山 聡;陰山聡(招待講演);Akira Kageyama (Invited lecture)
通讯作者：
Akira Kageyama (Invited lecture)