  It has been suggested that single and double jets observed emanating from
certain astrophysical objects may have a purely gravitational origin. We
discuss new classes of plane-fronted and pulsed gravitational wave solutions to
the equation for perturbations of Ricci-flat spacetimes around Minkowski
metrics, as models for the genesis of such phenomena. These solutions are
classified in terms of their chirality and generate a family of non-stationary
spacetime metrics. Particular members of these families are used as backgrounds
in analysing time-like solutions to the geodesic equation for test particles.
They are found numerically to exhibit both single and double jet-like features
with dimensionless aspect ratios suggesting that it may be profitable to
include such backgrounds in simulations of astrophysical jet dynamics from
rotating accretion discs involving electromagnetic fields.
