  The nonlinear dynamics of pulses in a two-temperature collisionless plasma
with formation of dispersion shock waves is studied. An analytical description
is given for arbitrary form of an initial disturbance with smooth enough
density profile on a uniform density background. For large time after the wave
breaking moment dispersive shock waves are formed. Motion of their edges is
studied in framework of Gurevich-Pitaevskii theory and Whitham theory of
modulations. The analytical results are compared with numerical solution.
