Journal
ASTROPHYSICAL JOURNAL
Volume 853, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.3847/1538-4357/aaa5b2
Keywords
accretion, accretion disks; instabilities; magnetohydrodynamics (MHD); turbulence
Categories
Funding
- Cyberscience Center, Tohoku University through the HPCI System Research Project [hp160131, hp170064]
- Computational Joint Research Program (Collaborative Research Project on Computer Science with High-Performance Computing) at the Institute for Space-Earth Environmental Research, Nagoya University
- Japan Society for the Promotion of Science [15H03730, 17K18798]
- Grants-in-Aid for Scientific Research [17K18798, 15H03730] Funding Source: KAKEN
Ask authors/readers for more resources
Magnetic turbulence in accretion disks under ideal magnetohydrodynamic (MHD) conditions is expected to be driven by the magneto-rotational instability (MRI) followed by secondary parasitic instabilities. We develop a three-dimensional ideal MHD code that can accurately resolve turbulent structures, and carry out simulations with a net vertical magnetic field in a local shearing box disk model to investigate the role of parasitic instabilities in the formation process of magnetic turbulence. Our simulations reveal that a highly anisotropic Kelvin-Helmholtz (K-H) mode parasitic instability evolves just before the first peak in turbulent stress and then breaks large-scale shear flows created by MRI. The wavenumber of the enhanced parasitic instability is larger than the theoretical estimate, because the shear flow layers sometimes become thinner than those assumed in the linear analysis. We also find that interaction between antiparallel vortices caused by the K-H mode parasitic instability induces small-scale waves that break the shear flows. On the other hand, at repeated peaks in the nonlinear phase, anisotropic wavenumber spectra are observed only in the small wavenumber region and isotropic waves dominate at large wavenumbers unlike for the first peak. Restructured channel flows due to MRI at the peaks in nonlinear phase seem to be collapsed by the advection of small-scale shear structures into the restructured flow and resultant mixing.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available