  We investigate the relaxation dynamics of magnetic vortex lines in type-II
superconductors following rapid changes of the external driving current by
means of an elastic line model simulated with Langevin molecular dynamics. A
system of flux vortices in a sample with randomly distributed point-like
defects is subjected to an external current of appropriate strength for a
sufficient period of time so as to be in a moving non-equilibrium steady state.
The current is then instantaneously lowered to a value that pertains to either
the moving or pinned regime. The ensuing relaxation of the flux lines is
studied via one-time observables such as their mean velocity and radius of
gyration. We have in addition measured the two-time flux line height
autocorrelation function to investigate dynamical scaling and aging behavior in
the system, which in particular emerge after quenches into the glassy pinned
state.
