  In conventional domain wall systems the aim of a high domain wall velocity
may be hindered by the occurrence of a Walker breakdown at comparably low
current density. We show how a Rashba interaction can stabilize the domain wall
dynamics and thereby shift the Walker breakdown to higher current densities.
The Rashba interaction creates a field like spin torque, which breaks the
symmetry of the system and modifies the internal structure of the domain wall.
Besides a shift of the Walker breakdown it can additionally induce a chirality
switch of the domain wall at sufficient Rashba fields. The preferred chirality
may then be chosen by the direction of the current flow. Both, the suppression
of the Walker breakdown and the chirality switching, affect the domain wall
velocity. This is even more pronounced for short current pulses, where an
additional domain wall movement after the pulse in either positive or negative
direction can determine the final position of the domain wall.
