  Controlling domain wall motion is important due to the impact on the
viability of proposed nanowire devices. One hurdle is slow domain wall speed
when driven by fields greater than the Walker field, due to nucleation of
vortices in the wall. We present simulation results detailing the dynamics of
these vortices; including the nucleation and subsequent fast ejection of the
vortex core leading to fast domain wall speeds. The ejection is due to the
reversal of the core moments by an out-of-plane field. The technique can be
used to produce domain walls of known orientation independent of the initial
state.
