  Understanding the behaviour of vortices under nanoscale confinement in
superconducting circuits is of importance for development of superconducting
electronics and quantum technologies. Using numerical simulations based on the
Ginzburg-Landau theory for non-homogeneous superconductivity in the presence of
magnetic fields, we detail how lateral confinement organises vortices in a long
superconducting nanostripe, and present a phase diagram of vortex
configurations as a function of the stripe width and magnetic field. We discuss
why average vortex density is reduced and reveal that confinement also has
profound influence on vortex dynamics in the dissipative regime under sourced
electrical current, mapping out transitions between asynchronous and
synchronous vortex rows crossing the nanostripe as the current is varied.
Synchronous crossings are of particular interest, since they cause single-mode
modulations in the voltage drop along the stripe in a high (typically
GHz-to-THz) frequency range.
