Collision of Quantized Vortices in Superfluid Helium and Effect of Applied Superflow.

Abstract

The turbulent state of superfluid helium at very low temperatures presents some important and unresolved problems. The turbulent state has a dense tangle of quantized vortex filaments that are characteristic of superfluid. Little is known, however, about their dynamics, particularly, interactive motion. The present paper studies numerically three-dimensional dynamics of two interacting vortex filaments. The equations of motion and the method of numerical calculation follow those of Schwarz. Two identical vortex rings which are initially placed far apart proceed abreast toward the same direction. They gradually become close due to their interaction, then suddenly collide. The critical distance where the collision occurs is determined by the competition between the local self-induced field of one ring and the nonlocal field from the partner. The critical distance is greatly influenced by an applied superflow field.