  All experiments, which have been proposed so far to model the
magnetorotational instability (MRI) in the laboratory, involve a Couette flow
of liquid metals in a rotating annulus. All liquid metals have small magnetic
Prandtl numbers, Pm, of about 10^{-6} (the ratio of kinematic viscosity to
magnetic diffusivity). With plasmas both large and small Pm are achievable by
varying the temperature and the density of plasma. Compressibility and fast
rotation of the plasma result in radial stratification of the equilibrium
plasma density. Evolution of perturbations in radially stratified viscous and
resistive plasma permeated by an axial uniform magnetic field is considered.
The differential rotation of the plasma is induced by the ExB drift in applied
radial electric field. Global unstable eigenmodes are calculated by our newly
developed matrix code. The plasma is shown to be MRI unstable for parameters
easily achievable in experimental setup.
