THE SATURATION LIMIT OF THE MAGNETOROTATIONAL INSTABILITY

Simulations of the magnetorotational instability (MRI) in a homogeneous shearing box have shown that the asymptotic strength of the magnetic field declines steeply with increasing resolution. Here I model the MRI-driven dynamo as a large-scale dynamo driven by the vertical magnetic helicity flux. This growth is balanced by large-scale mixing driven by a secondary instability. The saturated magnetic energy density depends almost linearly on the …