Cavity QED induced EM radiation 

Since time immemorial, man has been fascinated by atmospheric electricity. Yet, to this day the source of charge that produces the visible (VIS) light in lightning remains a mystery. Similarly, the discovery of static electricity by the early Greeks captured the imagination of man for over 2000 years, but otherwise is still unexplained. In 1933, the observation of VIS photons in the ultrasonic cavitations of water prompted research that has continued to the present day. In the1960, VIS photons and electrons were observed in flowing hydrocarbon liquids, the significance of which is the present-day interest in fires initiated by electrostatic discharge while pumping gasoline. We know that electrons and VIS photons may be produced by thermal ionization at high plasma temperatures, but the electrons and VIS photons in natural processes occur at ambient temperature.

At ambient temperature, a source of electromagnetic (EM) radiation having Planck energy at vacuum ultraviolet (VUV) frequencies is required to liberate electrons and
VIS photons. But the only EM energy available at ambient temperature is the thermal kT energy of atoms emitted as infrared (IR) radiation. At the very least, particles composed of atoms must somehow collectively produce VUV radiation to explain these observations. Moreover, the diversity of the conditions in which the electrons and VIS photons are observed suggests the mechanism by which VUV radiation is produced must have a universal character relying on the most fundamental of all principles of physics.

One theory by which VUV radiation is produced at ambient temperature is called cavity QED induced EM radiation. QED stands for quantum electrodynamics. Consider a particle of atoms having thermal kT energy confined within a surrounding annular QED cavity. A plurality of VUV waves stand in the gap between the particle and the cavity wall, one such VUV wave depicted in the 
 following sketch, 

The particle within the QED cavity may form by:

(1) the cavity wall separating from the particle, say in the nucleation of bubbles,
(2) the trapping of a particle by the cavity closing around it, say as a person
shoe stepping on a on a dust particle.

But free particles are not necessary. The extent of the QED cavity not only includes the gap, but also the penetration depth of the VUV standing wave beneath the surface of the cavity wall. Therefore, any QED cavity always contains the atoms within the penetration depth of standing resonant EM waves, e.g., the QED cavities comprising gaps between metal surfaces, as in contact electrification or the Casimir effect. Whether a particle or subsurface atoms, the IR radiation is suppressed because of the higher VUV resonance of the gap.