Non-axisymmetric Magnetorotational Instabilities in Cylindrical Taylor-Couette Flow

TL;DR

This paper investigates non-axisymmetric magnetorotational instabilities in cylindrical Taylor-Couette flow with azimuthal magnetic fields, identifying critical parameters that are experimentally accessible.

Contribution

It demonstrates the existence of non-axisymmetric MRI in cylindrical flow with specific critical parameters, expanding understanding of MRI behavior in laboratory settings.

Findings

Critical Reynolds number ~ 10^3

Critical Hartmann number ~ 10^2

Instabilities observable in PROMISE experiment

Abstract

We study the stability of cylindrical Taylor-Couette flow in the presence of azimuthal magnetic fields, and show that one obtains non-axisymmetric magnetorotational instabilities, having azimuthal wavenumber m=1. For Omega_o/Omega_i only slightly greater than the Rayleigh value (r_i/r_o)^2, the critical Reynolds and Hartmann numbers are Re_c ~ 10^3 and Ha_c ~ 10^2, independent of the magnetic Prandtl number Pm. These values are sufficiently small that it should be possible to obtain these instabilities in the PROMISE experimental facility.