All the above equations are for
To get equations for
waves you need only change the
signs of z and .Letting D denote a
wavefield and U an
wavefield, equation (21), for example,
is found in Table .6.
Using the exploding-reflector concept, it is the upcoming wave equation that is found in both migration and diffraction programs. The downgoing wave equation is useful for modeling and migration procedures that are more elaborate than those based on the exploding-reflector concept (chapter ).