Dynamics of coreless vortices and rotation-induced dissipation peak in superfluid films on rotating porous substrates

摘要

We analyze the dynamics of three-dimensional (3D) coreless vortices in superfluid films covering porous substrates. The 3D vortex dynamics is derived from the two-dimensional (2D) dynamics of the film. The motion of a 3D vortex is a sequence of jumps between neighboring substrate cells, which can be described, nevertheless, in terms of quasicontinuous motion with average vortex velocity. The vortex velocity is derived from the dissociation rate of vortex-antivortex pairs in a 2D film, which was developed in the past on the basis of the Kosterlitz-Thouless theory. The theory explains the rotation-induced dissipation peak in torsion-oscillator experiments on ~4He films on rotating porous substrates and can be used in the analysis of other phenomena related to vortex motion in films on porous substrates.