  We provide a new analysis of the system of partial differential equations
describing the radial and vertical equilibria of the plasma in accretion disks.
In particular, we show that the partial differential system can be separated
once a definite, oscillatory (or hyperbolic) form for the radial dependence of
the relevant physical quantities is assumed. The system is thus reduced to an
ordinary differential system in the vertical dimensionless coordinate. The
resulting equations can be integrated analytically in the limit of small
magnetic pressure. We complete our analysis with a direct numerical integration
of the more general case. The main result is that a ring-like density profile
(i.e., radial oscillations in the mass density) can appear even in the limit of
small magnetic pressure.
