Title: Upward and sideward radiation condition for wave in essentially
stratified midium and related inverse scattering problems

Abstract: 

Waves from a point source in a homogeneous medium will propagate spherically.
This can be described by the Sommerfeld radiation condition. However,
it is hard to use simple formula to describe radiation conditions for wave
propagation in a stratified medium. A generalized Sommerfeld radiation was
proposed by Xu in 1990, applying contour integral and asymptotic approximation.
The study in this area becomes more active recently. Papers in 2009 and 2010
from different aspects presented rigorous analysis for results similar to Xu's
condition. On the other hand, Chandler-Wilde and his coworkers introduced the
upward propagating radiation condition for wave in essentially homogeneous
medium with rough boundary.
 
This talk will discuss the radiation conditions for wave in essentially
stratified midium with unbounded inhomogeneity, and introduce an upward
propagating radiation condition and a sideward radiation condition for
waves in essentially layered medium. Some related inverse scattering problems
will be discussed.