Cover: Invariant imbedding, wave propagation, and the WKB approximation.

Invariant imbedding, wave propagation, and the WKB approximation.

Published 1957

by Richard Ernest Bellman, Robert E. Kalaba

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An attempt to indicate how wave propagation may be considered in terms of an over-all physical process as a sequence of local processes. The results are based on an algorithm that, in general, can yield divergent series. In addition, the paper shows that wave propagation can be discussed in terms of reflection and refraction at infinitesimally separated interfaces and that the convergence of the Bremmer series can be established under a simple assumption concerning the slowly varying nature of the local wave number.

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