The term, "scalar" as a necessary attribute to all electromagnetic phenomena was coined with fundamental equations that were introduced by James Clerk Maxwell in the 1860s and extended by Sir Edmund T. Whittaker in the early 1900s. Somehow, with time, "practical" engineers, not seeing what they could "do" with scalar potentials overlooked and then ignored them. In the early 1900s, Nikola Tesla applied these scalar potentials for several technologies, which were ignored by the financiers of the day - such as his system of the wireless transmission of electrical energy worldwide and for various very successful electrotherapeutic devices. In the 1970s, Lt-Col. Tom Bearden re-introduced the modern notion of scalar electromagnetics while a critical scientific experiment by Y. Aharonov and Nobelist David Bohm proved that the interferometry of 2 scalar potential beams results in "real" electromagnetic phenomena. Conversely, scalar electromagnetics can be engineered by symmetrically annulling like electromagnetic beams or waves. For example, in the Teslar device by Andrija Puharich, the scalars are produced by having the current that flows between the battery and the clocking mechanism go through a chip that contains mobius coils. In the Pulsors, ambient electromagnetics are selectively converted by George T. F. Yao into scalar electrodynamics with pre-set frequency bandwidths through micro-crystalline arrays. For the ELF Counteractors, ambient electromagnetics are converted into scalars at user-selected frequencies with special circuits designed by Eldon Byrd.
The 2 scalar potential
functions, F and G which completely characterize an electrodynamic
field for the fundamental case in which a field is due to any number of
electrons moving in any way are:
F (x, y, z, t) = sinh-1
G (x, y, z, t) = tan –1
These photons have an independent physical existence. Whittaker himself observed, after computation that the “total disturbance at any point, due to this system of waves, is independent of the time, and is everywhere proportional to the gravitational potential due to the particle at the point”.
Everything electromagnetic, and probably gravitational, starts from these scalar potentials, not fields, and under certain circumstances, there may exist photons without fields being present at all. In the vacuo, the longitudinal light photon travels in the direction of the beam, like an energy capsule, as a scalar four-potential-function energy standing-wave field, with many different frequencies, with an internal symmetry based on circular polarization  , an energy field or nexus that “has an end, but no beginning”. The time-like and space-like parts of the four potential are photons with spin –1, 0 and +1 that are longitudinally directed, and which are observed in the Compton and the photoelectric effect.
 Whittaker, Edmund T. On the partial differential equations of mathematical physics. Mathematische Annalen. Volume 57, 1903. p. 354.
 Evans, Myron W., and S. Kielich (editors). Modern nonlinear optics. [Special topical issue of Ilya Prigogine and Stuart A. Rice: Advances in Chemical Physics. Wiley, New York 1992, 1993, 1997, and 2001] Volume 85 (2).
 Institute for Advanced Study (Budapest). On Whittaker’s F and G fluxes, Part III: the existence of physical longitudinal and time-like photons. In: Higher symmetry electrodynamics: a collection of AIAS papers. [Special Issue. Journal of New Energy.] 2000. p. 7-1 – 7-5.