Work

One-winged butterflies: mode selection for azimuthal magnetorotational instability by thermal convection

Year: 2024

Type: article

Abstract: The effects of thermal convection on turbulence in accretion discs, and particularly its interplay with the magnetorotational instability (MRI), are of significant astrophysical interest. Despite extensive theoretical and numerical studies, such an interplay has not been explored experimentally. We conduct linear analysis of the azimuthal version of MRI (AMRI) in the presence of thermal convection and compare the results with our experimental data published before. We show that the critical Hartmann number ( $Ha$ ) for the onset of AMRI is reduced by convection. Importantly, convection breaks symmetry between $m = \pm 1$ instability modes ( $m$ is the azimuthal wavenumber). This preference for one mode over the other makes the AMRI wave appear as a ‘one-winged butterfly’.

Source: Journal of Fluid Mechanics

DOI: 10.1017/jfm.2024.517

Authors: Ashish Mishra, George Mamatsashvili, Martin Seilmayer, Frank Stefani

Institutions: Helmholtz-Zentrum Dresden-Rossendorf, Technische Universität Berlin, Evgeni Kharadze Georgian National Astrophysical Observatory

Language: English

Topic: Fluid Dynamics and Turbulent Flows

Subfield: Computational Mechanics

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,450

Funders: National Science Foundation, European Commission, Shota Rustaveli National Science Foundation, H2020 European Research Council