An Inverse Method for Determining Small Variations in Propagation Speed.

摘要

The inverse problem of determining small variations in propagation speed from observations of signals which pass through the medium of interest and are then observed remotely is considered. That the variation satisfies an integral equation of integral transform type with an atypical kernel is shown. In a variety of examples for the scalar and vector wave equation (Maxwell's equations) and the equations of linear elasticity, this integral equation is solved by elementary means.