  The motion of a collisionless plasma - a high-temperature, low-density,
ionized gas - is described by the Vlasov-Maxwell system. In the presence of
large velocities, relativistic corrections are meaningful, and when symmetry of
the particle densities is assumed this formally becomes the relativistic
Vlasov-Poisson system. These equations are considered in one space dimension
and two momentum dimensions in both the monocharged (i.e., single species of
ion) and neutral cases. The behavior of solutions to these systems is studied
for large times, yielding estimates on the growth of particle momenta and a
lower bound, uniform-in-time, on norms of the charge density. We also present
similar results in the same dimensional settings for the classical
Vlasov-Poisson system, which excludes relativistic effects.
