Convective, absolute and global azimuthal magnetorotational instabilities

We study the convective and absolute forms of azimuthal magnetorotational instability (AMRI) in a cylindrical Taylor–Couette (TC) flow with an imposed azimuthal magnetic field. We show that the domain of the convective AMRI is wider than that of the absolute AMRI. Actually, it is the absolute instab...

Full description

Saved in:
Bibliographic Details
Published in:Journal of fluid mechanics 2021-09, Vol.922, Article R4
Main Authors: Mishra, A., Mamatsashvili, G., Galindo, V., Stefani, F.
Format: Article
Language:English
Subjects:
Accretion disks
Direct numerical simulation
Eigenvalues
Experiments
Flow stability
JFM Rapids
Laboratories
Linear analysis
Magnetic domains
Magnetic field
Magnetic fields
Mathematical models
Propagation
Solar physics
Temporal variations
Traveling waves
Velocity
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We study the convective and absolute forms of azimuthal magnetorotational instability (AMRI) in a cylindrical Taylor–Couette (TC) flow with an imposed azimuthal magnetic field. We show that the domain of the convective AMRI is wider than that of the absolute AMRI. Actually, it is the absolute instability which is the most relevant and important for magnetic TC flow experiments. The absolute AMRI, unlike the convective one, stays in the device, displaying a sustained growth that can be experimentally detected. We also study the global AMRI in a TC flow of finite height using direct numerical simulation and find that its emerging butterfly-type structure – a spatio-temporal variation in the form of axially upward and downward travelling waves – is in a very good agreement with the linear analysis, which indicates the presence of two dominant absolute AMRI modes in the flow giving rise to this global butterfly pattern.
ISSN:0022-1120
1469-7645
DOI:10.1017/jfm.2021.548