ABSTRACT
The basis of the hydrodynamic analysis of superfluid helium carried out in Chap. 8 was the experimentally verified assertion that the superfluid motion is irrotational. It follows immediately from this that if we rotate a cylindrical bucket of superfluid helium, only the normal component should be carried along by the rotation. The superfluid part should remain stationary. This also follows from our simple microscopic picture. Indeed, when the bucket rotates the excitations collide with the walls and are carried along by the walls, so that the normal component of the liquid moves with the bucket. The superfluid component does not interact with the walls and remains stationary. However this conclusion is not confirmed experimentally. If the above picture were accurate, then the height of the meniscus formed in a rotating bucket of helium II would be smaller by a factor ρ n/ρ than the one formed in a classical liquid. But this is not what is observed experimentally. Rotating helium II forms a meniscus that has exactly the same height as that of a classical liquid. This means that experiment shows that when superfluid helium is rotated, the whole liquid is set into motion.
