Anomalous decay of turbulence in superfluid He4

The free decay of the quantized vortex tangle in a channel is observed to occur in two distinct stages, an initial rapid decay in agreement with current theory, followed by a regime of anomalously slow decay. It is argued that the second stage represents a state of coupled turbulence involving not only the quantized vortex tangle, but also macroscopic random motion of the normal and superfluid fields. © 1991 The American Physical Society.