0 Members and 1 Guest are viewing this topic.
Rick Autry asked the Naked Scientists: I'd like to see some kind of experiment to demonstrate the nature of the "soliton", and how to make the phenomenon visible to us visually oriented creatures...What do you think?
Duhhhhh, so what in the world is a "soliton"?
DefinitionA single, consensus definition of a soliton is difficult to find. Drazin and Johnson (1989) ascribe 3 properties to solitons: 1. They are of permanent form; 2. They are localised within a region; 3. They can interact with other solitons, and emerge from the collision unchanged, except for a phase shift.More formal definitions exist, but they require substantial mathematics. Moreover, some scientists use the term soliton for phenomena that do not quite have these three properties (for instance, the 'light bullets' of nonlinear optics are often called solitons despite losing energy during interaction).
Falaco Solitons are exhibitions of topological defects in a discontinuity surface.[ Kiehn 1986]. The phenomena is easily reproduced by placing a half-submerged circular disc (a Frisbee) in a swimming pool, then stroking the plate slowly in the direction of its oblate axis. At the end of the stroke extract the plate from the water, imparting kinetic energy and distributed angular momentum, to the fluid in the form of a pair of Rankine Vortices. In a few seconds, in bright sunlight, the concave Rankine depressions, with visible spiral arm caustics, will decay into a pair of convex dimples of negative Gauss curvature, which can be observed via their Snell projections as black spots on the bottom of the pool. In a few tries you will become an expert experimentalist, for the spots will persist for many minutes in a still pool.