Item Type: |
Article
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Erschienen: |
2010 |
Creators: |
Kirillov, O. N. and Stefani, F. |
Title: |
On the relation of standard and helical magnetorotational instability |
Language: |
English |
Journal or Publication Title: |
The Astrophysical Journal |
Journal volume: |
712 |
Divisions: |
16 Department of Mechanical Engineering > Dynamics and Vibrations 16 Department of Mechanical Engineering |
Date Deposited: |
19 Sep 2012 14:19 |
Identification Number: |
doi:10.1088/0004-637X/712/1/52 |
Alternative keywords: |
Alternative keywords | Language |
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accretion, accretion disks – instabilities – magnetohydrodynamics (MHD) – turbulence | English |
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Alternative Abstract: |
Alternative abstract | Language |
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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 behaviour 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 travelling wave (HMRI) and the excitation of HMRI in the inductionless limit. For certain parameter regions we find new islands of the HMRI. | English |
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