Comparison of the Vibrations of the Helium-II–Vapor Interface in a U-Shaped Channel with a Monodisperse Backfill and Without It

Experimental data on the movement of the superfluid helium in a U-shaped cylindrical channel filled with and without a permeable porous backfill of metal monodisperse spheres are considered. The results of experiments are presented in the form of the time dependences of the position of the helium-II–vapor interface in the channel. A comparison of the amplitudes and frequencies of vibration of this interface, depending on the pressure in the channel, in the cases of free channel and where it is filled with porous backfill has been performed. It is shown that, in the channel with a monodisperse porous backfill, a stationary state of the interface is possible.