Free-field propagation of localized pulses

Incident transient fields obey homogeneous Maxwell equations and are assumed to be a known input to the integral equations of electromagnetic scattering. These fields can be specified by two solenoidal fields for F-bar and B-bar at the initial time, and they can be computed at other times using the Green function for the scalar wave equation. Equations are derived that are then used in a computer program to do the integrations over the information-collecting sphere. Sample calculations show that a modulated pulse keeps its shape much better than a simple pulse.