%0 Journal Article %T On the nature of magnetic turbulence in rotating, shearing flows %+ Institut de Planétologie et d'Astrophysique de Grenoble (IPAG) %A Walker, Justin %A Lesur, Geoffroy %A Boldyrev, Stanislav %< avec comité de lecture %@ 1745-3933 %J Monthly Notices of the Royal Astronomical Society: Letters %I Oxford Journals %V 457 %P L39-L43 %8 2016 %D 2016 %Z 1512.03739 %Z 2016MNRAS.457L..39W %R 10.1093/mnrasl/slv200 %K accretion %K accretion discs %K dynamo %K MHD %K plasmas %K Astrophysics - Solar and Stellar Astrophysics %K Astrophysics - High Energy Astrophysical Phenomena %K Physics - Fluid Dynamics %K Physics - Plasma Physics %Z Sciences of the Universe [physics] %Z Sciences of the Universe [physics]/Astrophysics [astro-ph]Journal articles %X The local properties of turbulence driven by the magnetorotational instability (MRI) in rotating, shearing flows are studied in the framework of a shearing-box model. Based on numerical simulations, we propose that the MRI-driven turbulence comprises two components: the large-scale shear-aligned strong magnetic field and the small-scale fluctuations resembling magnetohydrodynamic (MHD) turbulence. The energy spectrum of the large-scale component is close to k-2, whereas the spectrum of the small-scale component agrees with the spectrum of strong MHD turbulence k-3/2. While the spectrum of the fluctuations is universal, the outer-scale characteristics of the turbulence are not; they depend on the parameters of the system, such as the net magnetic flux. However, there is remarkable universality among the allowed turbulent states - their intensity v0 and their outer scale λ0 satisfy the balance condition v00 ∼ dΩ/dln r, where dΩ/dln r is the local orbital shearing rate of the flow. Finally, we find no sustained dynamo action in the Pm = 1 zero net-flux case for Reynolds numbers as high as 45 000, casting doubts on the existence of an MRI dynamo in the Pm ≤ 1 regime. %G English %2 https://insu.hal.science/insu-03691562/document %2 https://insu.hal.science/insu-03691562/file/slv200.pdf %L insu-03691562 %U https://insu.hal.science/insu-03691562 %~ INSU %~ UNIV-SAVOIE %~ UGA %~ CNRS %~ INPG %~ IRSTEA %~ CNES %~ OSUG %~ IPAG %~ AGREENIUM %~ INRAE %~ UGA-COMUE %~ USMB-COMUE %~ TEST3-HALCNRS