  Magnetohydrodynamic (MHD) and two-fluid quasi-neutral equilibria with
azimuthal symmetry, gravity and arbitrary ratios of (nonrelativistic) flow
speed to acoustic and Alfven speeds are investigated. In the two-fluid case,
the mass ratio of the two species is arbitrary, and the analysis is therefore
applicable to electron-positron plasmas. The methods of derivation can be
extended in an obvious manner to several charged species. Generalized
Grad-Shafranov equations, describing the equilibrium magnetic field, are
derived. Flux function equations and Bernoulli relations for each species,
together with Poisson's equation for the gravitational potential, complete the
set of equations required to determine the equilibrium. These are
straightforward to solve numerically. The two-fluid system, unlike the MHD
system, is shown to be free of singularities. It is demonstrated analytically
that there exists a class of incompressible MHD equilibria with magnetic
field-aligned flow. A special sub--class first identified by S. Chandrasekhar,
in which the flow speed is everywhere equal to the local Alfven speed, is
compatible with virtually any azimuthally symmetric magnetic configuration.
Potential applications of this analysis include extragalactic and stellar jets,
and accretion disks.
