  The decay of quantum vortex rings in counterflow regimes, visualized in
Helium II with the help of solid hydrogen particles trapped to their cores, has
been a puzzling issue within the usual description of superfluid vortex
dynamics, grounded on the hypothesis that a vortex filament is, effectively, an
extended massless object subject to a canceling superposition of Magnus and
mutual friction forces. We discuss, from a general energy-budget point of view,
a phenomenological solution of this problem, which relies on viscous and
quantum dissipation mechanisms, the later associated to the backreaction of
vortex singular structures on the surrounding two-component fluid mixture.
