My Friends,
Tom Bearden used many terms, in the early days, Infolded was also used.
You may note, Tom Bearden has a whole book or slide show on Infolded Electrodynamics

The above slide, seen in the video.

Ref: Infolded Engines.

E.T Whittaker 1903 Cut
Remember: c + -c = 0?
It is a simple matter using the equations E / H = √με and c = 1 / √με for a team wave to get rid of H and C and so convert the first equation into the well known equation for energy density in the so-called electrostatic field:
ε = 1/2 ε E2
or
1/2 DE
Ref: Floyd Sweet - Nothing is Something
As always my friends, always lots to learn, thing is, we are Light Years Ahead already!
Just found:
Based on E.T. Whittaker's previously unnoticed 1903-1904 papers which established a hidden bidirectional EM wave structure in a standing forcefield free scalar potential, a method of directly engineering the ambient potential of the vacuum has been developed and realized experimentally. Adding Whittaker's engineerable hidden variable theory to classical electromagnetic, quantum mechanics, and general relativity produces supersets of each discipline. These supersets are joined by the common Whittaker subset, producing a unified field theory that is engineerable and tested. By treating the nucleus of the atom as a pumped phase conjugate mirror, several working model energy units have been produced which excite and organize the local vacuum, increase the local virtual photon flux between local vacuum and nucleus, establish coherent self-oscillations between the local excited vacuum and the affected nuclei, utilized the self-oscillating standing wave for self-pumping of the nuclei/mirrors, introduce a very tiny signal wave to the mirrors, and output into an external load circuit a powerful, amplified, time-reversed phase conjugate replica wave at 60 Hertz frequency and nominal 120 volt sine wave power. Several models have been built, ranging from 6 watts early on to one of 5 kilowatts. Both closed battery-less systems with damped positive feedback and open loop systems with battery-powered input have been successfully built. Open loop power gains of from 5 x 104 to 1.5 x 106 have been achieved. Antigravity experiments have also been successfully conducted where the weight of the unit was reduced by 90% in controlled experiments, with a signal wave input of 175 microwatts and an output of 1 kilowatt. The basic theory of the device is briefly explained and experimental results presented
Ref: IAEA - Utilizing scalar electromagnetics to tap vacuum energy
You can read the full paper here: Utilizing Scalar Electromagnetics To Tap Vacuum Energy
Under the oscillation Condition...
Best wishes, stay safe and well,
Chris