Spatiotemporally Localized Null Electromagnetic Waves I. Luminal

Spatiotemporally localized luminal null electromagnetic fields are transverse with respect to the local flow of energy,whic h is equipartioned between the electric and magnetic fields,and the modulus of their local energy transport velocity equals the speed of light in vacuo. They have vortex structures on planes transverse to the direction of propagation,and,in general,are relatively simple so that explicit calculations can be made of the total energy and the total angular momentum they carry. A class of luminal null electromagnetic waves due originally to Robinson and Troutman is motivated by means of spherical Cunningham and Bateman transformations and their relationships to well-known scalar luminal localized waves are examined. This allows for the introduction of finite-energy localized null luminal electromagnetic waves with spatiotemporal spectra appropriate for applications in diverse physical areas.