Acoustic and electromagnetic bullets
Abstract
We show that all finite energy, causal solutions of the timedependent threedimensional acoustic equation and Maxwell's equations have forms for large radius which, except for a factor 1/r represent onedimensional wave motions along straight lines through the origin. The asymptotic region is called the wave zone.We also show, conversely, how the exact finite energy causal solutions can be obtained from the asymptotic solutions in the wave zone through the use of a refined Radon transform. We have thus obtained a way of finding exact, causal threedimensional solutions from the essentially onedimensional solutions in the wave zone. When the asymptotic solutions are confined to a finite radial interval within a cone, the exact solutions are termed "bullets" and asymptotically represent packets of acoustic and electromagnetic energy "shot" through the cone. No reflectors are needed. Explicit examples will be given.
 Publication:

Microwave and Particle Beam Sources and Directed Energy Concepts
 Pub Date:
 July 1989
 DOI:
 10.1117/12.951821
 Bibcode:
 1989SPIE.1061..403M
 Keywords:

 Acoustic Propagation;
 Electroacoustics;
 Electromagnetic Pulses;
 Electromagnetic Wave Transmission;
 Asymptotic Methods;
 Boundary Value Problems;
 Maxwell Equation;
 Electronics and Electrical Engineering