soliton

A pulselike wave that can exist in nonlinear systems, does not obey the superposition principle, and does not disperse.

a self-reinforcing travelling wave or pulse caused by any non-linear effect; found in many physical systems

(physics) a quantum of energy or quasiparticle that can be propagated as a traveling wave in nonlinear systems and is neither preceded nor followed by another such disturbance; does not obey the superposition principle and does not dissipate