Transient currents on a cylinder illuminated by an impulsive plane wave

An analytical and numerical study of the transient current density induced on a perfectly conducting circular cylinder has been carried out. Both TE and TM incident plane waves with impulsive time dependence are considered. Complete closed form expressions for the TE and TM current density at all points on the cylinder and for all time values are obtained by a functional interpolation of both large and small time asymptotic solutions. The complete expressions should he useful in future transient radar scattering problems for approximating the transient current behavior on portions of a complex scatterer. The numerical results are presented in the form of "snapshots" of the current density at specific instants of time. The results are interpreted in terms of specular reflection and creeping waves. The creeping wave pulses are seen to be a continuation of pulses generated on the illuminated surface; their propagation into the shadow region is a highly dispersive phenomenon. The natural mode spectrum is seen to have both discrete and continuous components with the response at very large times determined by the latter.