Simulations of magnetorotational instability in a magnetized couette flow

Research output: Contribution to journalArticle

32 Scopus citations

Abstract

In preparation for an experimental study of magnetorotational instability (MRI) in liquid metal, we present non-ideal two-dimensional magnetohydrodynamic simulations of the nonlinear evolution of MRI in the experimental geometry. The simulations adopt initially uniform vertical magnetic fields, conducting radial boundaries, and periodic vertical boundary conditions. No-slip conditions are imposed at the cylinders. Our linear growth rates compare well with existing local and global linear analyses. The MRI saturates nonlinearly with horizontal magnetic fields comparable to the initial axial field. The rate of angular momentum transport increases modestly but significantly over the initial state. For modest fluid and magnetic Reynolds numbers Re, Rem ∼ 10 2 -103, the final state is laminar reduced mean shear except near the radial boundaries, and with poloidal circulation scaling as the square root of resistivity, in partial agreement with the analysis of Knobloch and Julien. A sequence of simulations at Rem = 20 and 102 ≲ Re ≲104.4 enables extrapolation to the experimental regime (Rem ≈ 20, Re ∼ 107), albeit with unrealistic boundary conditions. MRI should increase the experimentally measured torque substantially over its initial purely hydrodynamic value.

Original languageEnglish (US)
Pages (from-to)306-317
Number of pages12
JournalAstrophysical Journal
Volume643
Issue number1 I
DOIs
StatePublished - May 20 2006

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Accretion
  • Accretion disks
  • Instabilities
  • MHD
  • Methods: numerical

Fingerprint Dive into the research topics of 'Simulations of magnetorotational instability in a magnetized couette flow'. Together they form a unique fingerprint.

  • Cite this