Atoms in contact (9): Breaking the superfluid speed limit.

McClintock, Peter V. E. (1977) Atoms in contact (9): Breaking the superfluid speed limit. New Scientist, 73. pp. 651-653.

Abstract

The Russian physicist Lev Landau predicted that an object moving through a superfluid would meet no resistance - until a certain critical velocity. In this last of two articles on the motion of charged particles through superfluid helium the authors describe how they discovered an unexpected phenomenon when the ions exceeded the critical speed