  Charged particles interacting with electromagnetic waves have a portion of
their energy tied up in wave-driven oscillations. When these waves are
localized to the exhaust of linear magnetic confinement systems this
ponderomotive effect can be utilized to enhance particle confinement. The same
effect can be derived for particles moving via an $\mathbf{E} \times
\mathbf{B}$ drift into a region of a static perturbation to the electromagnetic
fields which has a large wave vector component in the direction of the motion.
In this work we use a simplified slab model to self-consistently solve for the
electromagnetic fields within the fluid flowing plasma of a static flute-like
($k_\parallel = 0)$ perturbation, and evaluate the resulting ponderomotive
potential. We find that two types of perturbations can exist within the flowing
plasma, which are an O wave and an X wave in the frame moving with the fluid.
In the case of tenuous plasma, these perturbations are magnetostatic or
electrostatic multipole-analog perpendicular to the guiding magnetic field in
the lab frame, respectfully. For denser plasmas, the O wave-like perturbation
is screened at the electron skin depth scale, and the X wave-like perturbation
is a combination of a similar perpendicular electric perturbation and parallel
magnetic perturbation. The ponderomotive potential generated in the X wave-like
case is gyrofrequency-dependent, and can be used as either potential barriers
or potential wells, depending on the direction of the flow velocity.
