  Magnetowave induced plasma wakefield acceleration (MPWA) in a relativistic
astrophysical outflow has been proposed as a viable mechanism for the
acceleration of cosmic particles to ultra high energies. Here we present
simulation results that clearly demonstrate the viability of this mechanism for
the first time. We invoke the high frequency and high speed whistler mode for
the driving pulse. The plasma wakefield so induced validates precisely the
theoretical prediction. We show that under appropriate conditions, the plasma
wakefield maintains very high coherence and can sustain high-gradient
acceleration over a macroscopic distance. Invoking gamma ray burst (GRB) as the
source, we show that MPWA production of ultra high energy cosmic rays (UHECR)
beyond ZeV 10^21 eV is possible.
