Possible origin of viscosity in the Keplerian accretion disks due to secondary perturbation: Turbulent transport without magnetic field

Abstract

The origin of hydrodynamic turbulence in rotating shear flow is a long standing puzzle. Resolving it is especially important in astrophysics when the flow angular momentum profile is Keplerian which forms an accretion disk having negligible molecular viscosity. Hence, any viscosity in such systems must be due to turbulence, arguably governed by magnetorotational instability especially when temperature T >~ 10^5. However, such disks around quiescent cataclysmic variables, protoplanetary and star-forming disks, the outer regions of disks in active galactic nuclei are practically neutral in charge because of their low temperature, and thus expected not to be coupled with the magnetic field appropriately to generate any transport due to the magnetorotational instability. This flow is similar to plane Couette flow including the Coriolis force, at least locally. What drives their turbulence and then transport, when such flows do not exhibit any unstable mode under linear hydrodynamic perturbation? We demonstrate that the threedimensional secondary disturbance to the primarily perturbed flow triggering elliptical instability may generate significant turbulent viscosity ranging 0.0001 <~ ν_t <~ 0.1 to explain transport in accretion flows.

13 pages including 3 figures; published in Research in Astronomy and Astrophysics

References in corpus (6)

• Hydrodynamic turbulence cannot transport angular momentum effectively in astrophysical disks
• Vortex generation in protoplanetary disks with an embedded giant planet
• Vortices in Thin, Compressible, Unmagnetized Disks
• Co-Accretion of Chondrules and Dust in the Solar Nebula
• An Exact, Three-Dimensional, Time-Dependent Wave Solution in Local Keplerian Flow
• Growing hydrodynamic modes in Keplerian accretion disks during secondary perturbations: Elliptical vortex effects

Cited by in corpus (6)

• Stability of quasi-Keplerian shear flow in a laboratory experiment
• Angular momentum transport and turbulence in laboratory models of Keplerian flows
• Growing pseudo-eigenmodes and positive logarithmic norms in rotating shear flows
• Stochastically driven instability in rotating shear flows
• Fate of an Accretion Disc around a Black Hole when both the Viscosity and Dark Energy is Effecting
• An optimal transient growth of small perturbations in thin gaseous discs