  Using scanning tunneling microscopy and Ginzburg-Landau simulations we
explore vortex configurations in magnetically coupled NbSe$_2$-Permalloy
superconductor-ferromagnet bilayer. The Permalloy film with stripe domain
structure induces periodic local magnetic induction in the superconductor
creating a series of pinning-antipinning channels for externally added magnetic
flux quanta. Such laterally confined Abrikosov vortices form quasi-1D arrays
(chains). The transitions between multichain states occur through propagation
of kinks at the intermediate fields. At high fields we show that the system
becomes non-linear due to a change in both the number of vortices and the
confining potential. The longitudinal instabilities of the resulting vortex
structures lead to vortices `levitating' in the anti-pinning channels.
