  We theoretically analyze quasi-one-dimensional Bose-Einstein condensates
under the influence of a harmonic trap and a narrow potential defect that moves
through the atomic cloud. Performing simulations on the mean field level, we
explore a robust mechanism in which a single dark soliton is nucleated and
immediately pinned by the moving defect, making it possible to drag it to a
desired position and release it there. We argue on a perturbative level that a
defect potential which is attractive to the atoms is suitable for holding and
moving dark solitons. The soliton generation protocol is investigated over a
wide range of model parameters and its success is systematically quantified by
a suitable fidelity measure, demonstrating its robustness against parameter
variations, but also the need for tight focusing of the defect potential.
Holding the soliton at a stationary defect for long times may give rise to
dynamical instabilities, whose origin we explore within a Bogoliubov-de Gennes
linearization analysis. We show that iterating the generation process with
multiple defects offers a perspective for initializing multiple soliton
dynamics with freely chosen initial conditions.
