  We explore heavy element nucleosynthesis in neutrino-driven winds from
rapidly-rotating, strongly magnetized proto-neutron stars for which the
magnetic dipole is aligned with the rotation axis, and the field is assumed to
be a static force-free configuration. We process the proto-magnetar wind
trajectories calculated by Vlasov et al 2014 through the r-process nuclear
reaction network SkyNet using contemporary models for the evolution of the wind
electron fraction during the proto-neutron star cooling phase. Although we do
not find a successful second or third peak r-process for any rotation period P,
we show that proto-magnetars with P around 1-5 ms produce heavy element
abundance distributions that extend to higher nuclear mass number than from
otherwise equivalent spherical winds (with the mass fractions of some elements
enhanced by factors of 100-1000). The heaviest elements are synthesized by
outflows emerging along flux tubes which graze the closed zone and pass near
the equatorial plane outside the light cylinder. Due to dependence of the
nucleosynthesis pattern on the magnetic field strength and rotation rate of the
proto-neutron star, natural variations in these quantities between core
collapse events could contribute to the observed diversity of the abundances of
weak r-process nuclei in metal-poor stars. Further diversity, including
possibly even a successful third-peak r-process, could be achieved for
misaligned rotators with non-zero magnetic inclination with respect to the
rotation axis. If proto-magnetars are central engines for GRBs, their
relativistic jets should contain a high mass fraction of heavy nuclei of
characteristic average mass number A of order 100, providing a possible source
for ultra-high energy cosmic rays comprised of heavy nuclei with an energy
spectrum that extends beyond the nominal GZK cut-off for protons or iron
nuclei.
