1991/07/01 by Steven A. Balbus, John F. Hawley · 14 citations
Physics and Astronomy · #Astro and Planetary Science #Stellar, planetary, and galactic studies #Astrophysics and Star Formation Studies
paper · doi:10.1086/170270
openalex publication_date 1991/07/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
A broad class of astronomical accretion disks is presently shown to be dynamically unstable to axisymmetric disturbances in the presence of a weak magnetic field, an insight with consequently broad applicability to gaseous, differentially-rotating systems. In the first part of this work, a linear analysis is presented of the instability, which is local and extremely powerful; the maximum growth rate, which is of the order of the angular rotation velocity, is independent of the strength of the magnetic field. Fluid motions associated with the instability directly generate both poloidal and toroidal field components. In the second part of this investigation, the scaling relation between the instability's wavenumber and the Alfven velocity is demonstrated, and the independence of the maximum growth rate from magnetic field strength is confirmed.