  The aim of this work is to investigate and characterise particle behaviour in
a 3D magnetohydrodynamic (MHD) model of a reconnecting magnetic separator. We
use a relativistic guiding-centre test-particle code to investigate electron
and proton acceleration in snapshots from 3D MHD separator reconnection
experiments, and compare the results with findings from an analytical separator
reconnection model studied in a previous investigation. The behaviour and
acceleration of large distributions of particles are examined in detail for
both analytical and numerical separator reconnection models. Accelerated
particle orbit trajectories are shown to follow the separator before leaving
the system along the separatrix surface of one of the nulls (determined by
particle species) in the system of both models. A sufficiently localised
electric field about the separator causes the orbits to appear to follow the
spine bounding the separatrix surface field lines instead. We analyse and
discuss the locations and spread of accelerated particle orbit final positions,
which are seen to change over time in the numerical separator reconnection
model. We deduce a simple relationship between the final energy range of
particle orbits and the model dimensions, and discuss its implications for
observed magnetic separators in the solar corona.
