The magnetorotational instability ( MRI ) is a shear instability and thus its sensitivity to the shear parameter q = - d \ln \Omega / d \ln r is of interest to investigate .
Motivated by astrophysical disks , most ( but not all ) previous MRI studies have focused on the Keplerian value of q = 1.5 .
Using simulation with 8 vertical density scale heights , we contribute to the subset of studies addressing the the effect of varying q in stratified numerical simulations .
We discuss why shearing boxes can not easily be used to study q > 2 and thus focus on q < 2 .
As per previous simulations , which were either unstratified or stratified with a smaller vertical domain , we find that the q dependence of stress for the stratified case is not linear , contrary to the Shakura-Sunyaev model .
We find that the scaling agrees with ( ) who found it to be proportional to the shear to vorticity ratio q / ( 2 - q ) .
We also find however , that the shape of the magnetic and kinetic energy spectra are relatively insensitive to q and that the ratio of Maxwell stress to magnetic energy ratio also remains nearly independent of q .
This is consistent with a theoretical argument in which the rate of amplification of the azimuthal field depends linearly on q and the turbulent correlation time \tau depends inversely on q .
As such , we measure the correlation time of the turbulence and find that indeed it is inversely proportional to q .