\section{Numerical Simulations of MRI}
The MRI was first considered in the stellar context by \citet{Balbus_1994}. \citet{Menou_2004} extended the analysis to consider the effects of viscous, magnetic, and thermal diffusion. More recently, simulations by \citet{Obergaulinger_2006,Obergaulinger_2009} and analytic work by \citet{Wheeler_2015} have been applied to the study of massive stars, while \citet{Spada_2016} used the results of a single simulation of the MRI to calibrate a prescription for internal angular momentum transport. The latter group showed encouraging results when compared to the observed red giant cores rotation rate. However, this stands on MRI simulation that do not include the important effects of mean molecular weight, particularly relevant in the differentially rotating regions of ascending RGB \citep[e.g.][]{Cantiello_2014}.  