The total \dot{\phi}(t) waveform of a square-loop magnetic core switched by MMF F(t) from negative remanence \phi = -\phi_{r} is composed of elastic \dot{\phi}_{\epsilon}(t) , decaying inelastic \dot{\phi}_{i}(t) , and bell-shaped main inelastic \dot{\phi}_{ma}(t) . The worst delta noise in a coincident-current memory core pair is essentially \dot{\phi}_{i}(t) . The sources of these components and the static \phi(F) curve are explained qualitatively by means of the random variations of the energy gradient vs. domain-wall position: elastic wall displacements and elastic rotation of magnetization induce \dot{\phi}_{\epsilon}(t) ; minor inelastic wall displacements of essentially constant wall areas induce \dot{\phi}_{i}(t) ; and major inelastic wall displacements (involving domain collisions) of varying wall areas induce \dot{\phi}_{ma}(t) . Semiempirical models for the \dot{\phi} components are based on the characteristics of these displacements. A satisfactory agreement is obtained between these models and \dot{\phi}(t) oscillograms of a thin ferrite core.