I put up a new paper “On Hydromagnetic Stresses in Weakly Magnetized Stellar Boundary Layers” on arXiv. Here is the abstract:
We examine the generation of hydromagnetic stresses and energy density in the boundary layer around a weakly magnetized star in the shearing-sheet approximation. This region, where the angular frequency is expected to increases with radius, is stable against the magnetorotational instability. We provide analytic solutions for the long-term evolution of shearing MHD waves, which exhibit non-trivial dynamics. Even though their associated stresses oscillate around zero, their energy density can be amplified significantly. This is consistent with the findings of numerical simulations of MHD boundary layers and suggest that their detailed structure could differ appreciably from those derived within the standard framework of turbulent viscosity.
The paper is also submitted to ApJ. Hopefully it will be accepted soon!