FULLY CONVECTIVE MAGNETOROTATIONAL TURBULENCE IN LARGE ASPECTRATIO SHEARING BOXES
We present a numerical study of turbulence and dynamo action in stratified shearing boxes with both finite and zero net magnetic flux. We assume that the fluid obeys the perfect gas law and has finite thermal diffusivity. The latter is chosen to be small enough so that vigorous convective states develop. The properties of these convective solutions are analyzed as the aspect ratio of the computational domain is varied and as the value of the mean field is increased. For the cases with zero net flux, we find that a welldefined converged state is obtained for large enough aspect ratios. In the converged state, the dynamo can be extremely efficient and can generate substantial toroidal flux. We identify solutions in which the toroidal field is mostly symmetric about the midplane and solutions in which it is mostly antisymmetric. The symmetric solutions are found to be more efficient at transporting angular momentum and can give rise to a luminosity that is up to an order of magnitude larger than the corresponding value for the antisymmetric states. In the cases with a finite net flux, the system appears to spend most of the time in the symmetric states.
 Authors:

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 INAF, Osservatorio Astronomico di Torino, Strada Osservatorio 20, I10025 Pino Torinese (Italy)
 The Computation Institute, The University of Chicago, 5735 South Ellis Avenue, Chicago, IL 60637 (United States)
 Dipartimento di Fisica, Univesità di Torino, via Pietro Giuria 1, I10125 Torino (Italy)
 Publication Date:
 OSTI Identifier:
 22364560
 Resource Type:
 Journal Article
 Resource Relation:
 Journal Name: Astrophysical Journal; Journal Volume: 799; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
 Country of Publication:
 United States
 Language:
 English
 Subject:
 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCRETION DISKS; ANGULAR MOMENTUM; ASPECT RATIO; LUMINOSITY; MAGNETIC FLUX; MAGNETOHYDRODYNAMICS; MATHEMATICAL SOLUTIONS; MEANFIELD THEORY; NUMERICAL ANALYSIS; SHEAR; SYMMETRY; THERMAL DIFFUSIVITY; TURBULENCE