Kink‐assisted mode hopping in a resonator.

For a sufficiently large fixed drive amplitude, a localized kink structure is observed to spontaneously participate in the transition of one standing wave mode to another as the drive frequency is slowly changed. The observations are of gravity waves in a parametrically driven annular channel of liquid. The kink, which can occur at any location around the resonator, has a substantially greater amplitude and shorter wavelength than the extended mode region. Such a structure is predicted to exist according to a theory that simultaneously allows amplitude and wave‐number modulations of a finite‐amplitude standing wave. The situation is in fundamental contrast to nonlinear Schrodinger (NLS) solitons, which correspond to only amplitude modulations, and to all other known types of solitons. Observations and theory of the NLS structures will be reviewed, and their role in the discovery of the new kinks will be discussed. The possibility of propagating versions of the new kinks, and of applications to fiber optic...