Title: Dynamo-generated Turbulence and Large-Scale Magnetic Fields in a Keplerian Shear Flow
Abstract:view Abstract Citations (724) References (63) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Dynamo-generated Turbulence and Large-Scale Magnetic Fields in a Kepleria...view Abstract Citations (724) References (63) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Dynamo-generated Turbulence and Large-Scale Magnetic Fields in a Keplerian Shear Flow Brandenburg, Axel ; Nordlund, Ake ; Stein, Robert F. ; Torkelsson, Ulf Abstract The nonlinear evolution of magnetized Keplerian shear flows is simulated in a local, three-dimensional model, including the effects of compressibility and stratification. Supersonic flows are initially generated by the Balbus-Hawley magnetic shear instability. The resulting flows regenerate a turbulent magnetic field which, in turn, reinforces the turbulence. Thus, the system acts like a dynamo that generates its own turbulence. However, unlike usual dynamos, the magnetic energy exceeds the kinetic energy of the turbulence by a factor of 3-10. By assuming the field to be vertical on the outer (upper and lower) surfaces we do not constrain the horizontal magnetic flux. Indeed, a large-scale toroidal magnetic field is generated, mostly in the form of toroidal flux tubes with lengths comparable to the toroidal extent of the box. This large-scale field is mainly of even (i.e., quadrupolar) parity with respect to the midplane and changes direction on a timescale of ∼30 orbits, in a possibly cyclic manner. The effective Shakura-Sunyaev alpha viscosity parameter is between 0.001 and 0.005, and the contribution from the Maxwell stress is ∼3-7 times larger than the contribution from the Reynolds stress. Publication: The Astrophysical Journal Pub Date: June 1995 DOI: 10.1086/175831 Bibcode: 1995ApJ...446..741B Keywords: ACCRETION; ACCRETION DISKS; MAGNETOHYDRODYNAMICS: MHD; SHOCK WAVES; TURBULENCE full text sources ADS |Read More
Publication Year: 1995
Publication Date: 1995-06-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 739
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