Decay of counterflow He II turbulence in a finite channel: possibility of missing links between classical and quantum turbulence.

Decay of He II counterflow turbulence generated by applying a heat pulse to the closed end of a circular channel is investigated using second sound attenuation. Several orders of magnitude of decaying vortex line density display various regimes, starting with the inverse time decay predicted by Vinen towards distinct classical t(-3/2) power law occurring after saturation of the energy containing length scale by the size of the channel. The decaying counterflow turbulence displays a surprisingly close resemblance to recently reported decaying grid turbulence in He II, and both of them appear closely linked to classical grid generated turbulence.