Decay of vortex tangle in superfluid He-4 at very low temperatures

摘要

Recently, the Lancaster group observed the free decay of vortex tangle in superfluid He-4 at mK temperatures. Since the system at such low temperatures is free from the normal fluid and the usual mutual friction, the mechanism of the free decay is unknown. In order to understand these phenomena, this work studies numerically the vortex dynamics without the mutual friction. The absence of mutual friction prevents the vortex from smoothing. The resulting kinked structure promotes vortex reconnection, thus making lots of vortex loops with small size. Such cascade process as breakup of vortices to smaller ones and the nonlocal interaction can decay the length of vortices. (C) 2000 Elsevier Science B.V. All rights reserved. [References: 4]