Magnetohydrodynamics

The magnetorotational instability (MRI) is considered to be one of the most powerful sources turbulence in hydrodynamically stable quasi-Keplerian flows, such as those governing accretion disk flows. Although linear stability these flows with applied external magnetic field has been studied for decades, influence on outward angular momentum transport, necessary disk, still not well known. In this work we model Keplerian rotation Taylor-Couette flow and imposed azimuthal using both nonlinear approaches. We present scalings Hartmann Reynolds numbers via analysis direct numerical simulations (DNS) two Prandtl $1.4 \cdot 10^{-6}$ $1$. Inside domains modes different axial wavenumbers dominate, resulting sub-domains instabilities, which appear each $Pm$. DNS show emergence 1- 2-frequency spatio-temporally oscillating structures $Pm=1$ close onset instability, significant enhancement transport compared $Pm=1.4 10^{-6}$.