On the relation of standard and helical magnetorotational instability

Kirillov, Oleg and Stefani, Frank (2010) On the relation of standard and helical magnetorotational instability. The Astrophysical Journal, 712 (1). pp. 52-68. ISSN 0004-637X

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Official URL: http://dx.doi.org/10.1088/0004-637X/712/1/52

Abstract

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.

Item Type: Article
Uncontrolled Keywords: accretion, accretion disks – instabilities – magnetohydrodynamics (MHD) – turbulence
Subjects: F300 Physics
F500 Astronomy
G100 Mathematics
Department: Faculties > Engineering and Environment > Mathematics and Information Sciences
Depositing User: Oleg Kirillov
Date Deposited: 23 Jan 2017 12:40
Last Modified: 08 May 2017 19:44
URI: http://nrl.northumbria.ac.uk/id/eprint/29282

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