Saturation of the magnetorotational instability by stable magnetoacoustic modes

Edward Liverts, Yuri Shtemler, Michael Mond, Orkan M. Umurhan, Dmitry V. Bisikalo

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


The magnetorotational instability (MRI) of thin, vertically-isothermal Keplerian discs, under the influence of an axial magnetic field is investigated near the instability threshold. The nonlinear interaction of Alfven-Coriolis (MRI) modes with stable magnetoacoustic waves is considered. The transition of the Alfven-Coriolis modes to instability occurs when the linearized system has zero eigenvalue of multiplicity two. As a result the nonlinear ordinary differential equation that describes the evolution of the amplitude of the MRI mode near the threshold is of second order. Solutions of that amplitude equation reveal that the MRI is saturated to bursty periodical oscillations due to the transfer of energy to the stable magnetosonic modes.

Original languageEnglish
Title of host publicationSolar and Astrophysical Dynamos and Magnetic Activity
PublisherCambridge University Press
Number of pages2
ISBN (Print)9781107033832
StatePublished - 1 Jan 2012

Publication series

NameProceedings of the International Astronomical Union
ISSN (Print)1743-9213
ISSN (Electronic)1743-9221


  • Accretion
  • instabilities
  • magnetohydrodynamics

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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