2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/123433We report on a new type of localized structure, an ultrasonic cavity soliton, supported by large aspect-ratio acoustic resonators containing viscous media. The spatio-temporal dynamics of this system is analyzed on the basis of a generalized Swift-Hohenberg equation, derived from the microscopic equations under conditions close to nascent bistability. These states of the acoustic and thermal fields are robust structures, existing whenever a spatially uniform solution and a periodic pattern coexist. An analytical solution for the ultrasonic cavity soliton is also presented.Pattern Formation and Solitonstext