  The theory of controlled mechanical systems of [6, 3, 4] is extended to the
case of ideal incompressible fluids consisting of charged particles in the
presence of an external magnetic field. The resulting control is of feedback
type and depends on the Eulerian state of the controlled system. Moreover, the
control is set up so that the corresponding closed loop equations are
Lie-Poisson. This implies that the energy-momentum method of [1, 11] can be
used to find a stabilizing control. As an example the case of planar parallel
shear flow with an inflection point is treated. A state dependent feedback
control is constructed which stabilizes the system for an arbitrarily long
channel.
