Dynamo Induced by Time-periodic Force

被引:1
|
作者
Wei, Xing [1 ]
机构
[1] Shanghai Jiao Tong Univ, Inst Nat Sci, Sch Math Sci, Shanghai, Peoples R China
关键词
dynamo; PRECESSION; DRIVEN; LIBRATION;
D O I
10.3847/2041-8213/aab08a
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
To understand the dynamo driven by time-dependent flow, e.g., turbulence, we investigate numerically the dynamo induced by time-periodic force in rotating magnetohydrodynamic flow and focus on the effect of force frequency on the dynamo action. It is found that the dynamo action depends on the force frequency. When the force frequency is near resonance the force can drive dynamo, but when it is far away from resonance dynamo fails. In the frequency range near resonance to support dynamo, the force frequency at resonance induces a weak magnetic field and magnetic energy increases as the force frequency deviates from the resonant frequency. This is opposite to the intuition that a strong flow at resonance will induce a strong field. It is because magnetic field nonlinearly couples with fluid flow in the self-sustained dynamo and changes the resonance of driving force and inertial wave.
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页数:6
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