  Almost any use of a superconductor implies a nonequilibrium state.
Remarkably, the non-equilibrium states induced by a microwave stimulus and the
dynamics of magnetic flux quanta (Abrikosov vortices) can give rise to
strikingly contrary effects: A sufficiently high-power electromagnetic field of
GHz frequency can stimulate superconductivity, whereas fast vortex motion can
trigger an instability abruptly quenching the superconducting state. Here, we
advance or delay such dynamical quenching of the vortex state in Nb thin films
by tuning the power and frequency of the microwave ac stimulus added to a dc
bias current. The experimental findings are supported by time-dependent
Ginzburg-Landau simulations and they can be explained qualitatively based on a
model of "breathing mobile hot spots", implying a competition of heating and
cooling of quasiparticles along the trajectories of moving fluxons whose core
sizes vary in time. In addition, we demonstrate universality of the stimulation
effect on the thermodynamic and transport properties of type II
superconductors.
