  We study the dynamics of the striped phase, which has previously been
suggested to be the ground state of a doped antiferromagnet. Starting from the
t-J model, we derive the classical equation governing the motion of the charged
wall by using a ficticious spin model as an intermediate step. A wave-like
equation of motion is obtained and the wall elasticity and mass density
constants are derived in terms of the t and J parameters. The wall is then
regarded as an elastic string which will be trapped by the pinning potential
produced by randomly distributed impurities. We evaluate the pinning potential
and estimate the threshold electric field which has to be applied to the system
in order to release the walls. Besides, the dynamics of the stripe in the
presence of a bias field below the threshold is considered and the high- and
low-temperature relaxation rates are derived.
