Flux Bottlenecks in the Mass Superflux in Solid Helium

Superfluid \4he atoms are injected (withdrawn) asymmetrically into (from) a chamber filled with solid \4he. Two in situ capacitance pressure gauges are located at the ends of the solid helium sample at different distances from where the superfluid meets the solid \4he. The pressure change kinetics are slower at the more distant gauge. This demonstrates the presence of a mass flux bottleneck inside the solid helium sample. The temperature dependence of the maximum flux reveals a crossover and this is discussed in the context of phase slips on quasi-1-D pathways.