Reconnection of quantized vortices in superfluid 4He

Three-dimensional dynamics of two interacting quantized vortex filaments is studied. The equations of motion and the method of numerical calculation follow Schwarz. The present paper describes when and how two filaments approach to reconnect; the obtained results differ from the assumption Schwarz used in the simulation of vortex tangle. Whether two approaching filaments reconnect or not depends on their arrangement before approach. When a ring moves toward a line from a distance, for example, there is a critical initial distance only within which they can reconnect. The critical distance is minimized when their circulations are parallel at the closet place, while it increases as their circulations become to deviate from being parallel. In such a symmetrical case as collision of two same rings, they can make some extensive twists on themselves to reconnect. Our results are compared with the numerical simulation by Schwarz. (author)