The atmospheric pressure wave generated by a nuclear explosion: 1.

The problem of describing the pressure wave detected by an observer on the ground a few thousand kilometers from a low-altitude nuclear explosion is formulated. To avoid numerical complications, the atmosphere is assumed to have an isothermal temperature distribution. With this simplification a Green's function for the problem is developed as an expansion in Legendre polynomials. This representation yields a time-dependent pressure function which satisfies the condition of causality but which converges far too slowly to be useful. An alternative scheme, which is entirely equivalent, makes use of a Watson transformation and requires the determination of the set of Regge poles. The behavior of the complete Green's function is then shown to be dominated by the so-called gravity wave mode, and the form of this approximate solution is developed.