ON THE RELATION OF STANDARD AND HELICAL MAGNETOROTATIONAL INSTABILITY
ON THE RELATION OF STANDARD AND HELICAL MAGNETOROTATIONAL INSTABILITY
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DOI：
10.1088/0004-637x/712/1/52
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发表时间：
2009-10
期刊：
影响因子：
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通讯作者：
Oleg N. Kirillov;F. Stefani
中科院分区：
文献类型：
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作者：
Oleg N. Kirillov;F. Stefani
磁旋转不稳定性（MRI）在开普勒盘中产生湍流，从而在宇宙结构的形成中发挥着至关重要的作用，否则开普勒盘在流体动力学上是稳定的。特别关注磁性普朗特数较小的液态金属的 MRI 实验，结果表明，这种不稳定性的螺旋版本 (HMRI) 具有与标准 MRI (SMRI) 完全不同的缩放行为。我们通过探索各种参数依赖性来讨论 HMRI 与 SMRI 的关系。我们通过光谱异常点确定了模式之间不稳定转移的机制，该异常点解释了从稳态不稳定性 (SMRI) 到不稳定行波 (HMRI) 的转变以及 HMRI 在无感应极限下的激发。对于某些参数区域，我们发现了 HMRI 的新岛。
The magnetorotational instability (MRI) plays a crucial role for cosmic structure formation by enabling turbulence in Keplerian disks which would be otherwise hydrodynamically stable. With particular focus on MRI experiments with liquid metals, which have small magnetic Prandtl numbers, it has been shown that the helical version of this instability (HMRI) has a scaling behavior that is quite different from that of the standard MRI (SMRI). We discuss the relation of HMRI to SMRI by exploring various parameter dependencies. We identify the mechanism of transfer of instability between modes through a spectral exceptional point that explains both the transition from a stationary instability (SMRI) to an unstable traveling wave (HMRI) and the excitation of HMRI in the inductionless limit. For certain parameter regions, we find new islands of the HMRI.