title: Faraday instability of superfluid surface.
abstract: We observed that Faraday waves are parametrically generated on a free surface of superfluid 4He when a sample cell is vibrated vertically. Standing-wave patterns appear on the surface, and their frequencies are one-half the driving frequency. We observed clear threshold amplitudes of the vibration for the instability. The difference in the threshold between the superfluid and the normal fluid is explained by a wall damping.
authors.affiliation: Department of Condensed Matter Physics, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro, Tokyo 152-8551, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Abe
authors.forename: Tetsuto
authors.initials: T
authors.lastname: Ueda
authors.forename: Michihiro
authors.initials: M
authors.lastname: Morikawa
authors.forename: Yu
authors.initials: Y
authors.lastname: Saitoh
authors.forename: Ryuji
authors.initials: R
authors.lastname: Nomura
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Okuda