title: Stimulated acoustic emissions from coupled strings.
abstract: We consider traveling transverse waves on two identical uniform taut strings that are elastically coupled through springs that gradually decrease their stiffness over a region of finite length. The wave system can be decomposed into two modes: an in-phase mode ([Formula: see text]) that is transparent to the coupling springs, and an out-of-phase mode ([Formula: see text]) that engages the coupling springs and can resonate at a particular location depending on the excitation frequency. The system exhibits linear mode conversion whereby an incoming ([Formula: see text]) wave is reflected back from the resonance location both as a propagating ([Formula: see text]) wave and an evanescent ([Formula: see text]) wave, while both types emerge as propagating forward through the resonance location. We match a local transition layer expansion to the WKB expansion to obtain estimates of the reflection and transmission coefficients. The reflected waves may be an analog for stimulated emissions from the ear.
authors: Section on Auditory Mechanics, NIDCD-National Institute on Deafness and Other Communication Disorders, Bethesda, MD USA.
authors: Richard S
authors: RS
authors: Chadwick
authors: Section on Auditory Mechanics, NIDCD-National Institute on Deafness and Other Communication Disorders, Bethesda, MD USA.
authors: Jessica S
authors: JS
authors: Lamb
authors: Division of Applied Mathematics, Department of Sciences, Technical University of Crete, Hania, Crete Greece.
authors: Daphne
authors: D
authors: Manoussaki
keywords: Acoustic emissions; Asymptotic matching of inner and outer expansions; Coupled wave propagation; Mode conversion; WKB approximation