  We address here the superconductivity quenching under an external magnetic
field of amplitudes up to 1 T and in the so-called "thermal smallness"
condition, when the microbridge width becomes smaller than the thermal
diffusion length of both the own superconductor and its refrigerant (the
substrate, in the case of thin films), which breaks their thermal dimensional
scaling. Our results further support that when the current perturbations have
characteristic times in the millisecond range the quenching is due to thermal
instabilities associated with regular (nonsingular) flux-flow, and they also
suggest how to optimize the refrigeration of practical superconductors.
