Alternate proof of the optical theorem for impenetrable targets.
The optical theorem is proven for impenetrable targets without using the method of stationary phase. The proof depends upon the divergence theorem, the Helmholtz representation of the scattered field, and the law of cosines.
Kriegsmann
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GA
Department of Mathematical Sciences, Center for Applied Mathematics and Statistics, New Jersey Institute of Technology, University Heights, Newark, New Jersey 07102, USA.