The plasmoid can be thought of as an electromagnetic black hole. It is a bubble of electromagnetic radiation that is cut-off from the remainder of space.
The negative charge layer on the outside surface of the plasmoid forces all emf radiation inward (normal) toward the center of the plasmoid. Because the plasmoid lasts a long time, it does not radiate the energy that is stores. It is like a capacitor that holds vast amounts of energy. Large amounts of power, 800 joules in our case, are concentrated into a volume that is only a few centimeters in diameter. The interior of the plasmoid is disconnected from the EMF fields outside the plasmoid by the large negative charge localized on its outer skin. The plasmoid will convert energy perturbations that occur immediately outside its boundaries and around it to increases in its stores of power. Puthoff has suggested that by introducing the zero-point-field (ZPF) into this energy transfer process, the great electromagnetic stability that the plasmoid demonstrates may be greatly enhanced. Conducting systems will experience a net outside pressure, analogous to the Casimir force, due to the exclusion of ZPF frequencies from the center of the plasmoid. The more kinetic energy that the plasmoid stores in its interior, the smaller it gets and the more charge is concentrated on its outer surface to contain that energy. The more conducting the negatively charged surface, the higher the frequencies on the outer surface grows, the more ZPF modes will be excluded from the interior and the higher the vacuum pressure differential. The plasmoid does, in fact, demonstrate high EMF stability that implies radiation free stability. Additionally, the energy to stabilize these non-radiating EMF plasmoid modes might be available from the higher frequencies in the ZPF, once the plasmoid has been formed. If the above theory is to be believed, The ZPF may play an important role in stabilizing non-radiating modes in the plasmoid and if the process is one that demonstrates positive feedback, the plasmoid may also demonstrated energy gain. Detailed calculations would have to be done to determine critical densities of charge versus size and frequency for all the quantities to come together exactly right. Further research would investigate how to inject additional charge into already-formed modes, and have them stabilized by higher frequencies that come from directed sources, or are present in the ZPF. A final point relates to the initial construction of non-radiating EMF modes. If these modes are stable, why are they not a common phenomenon? Actually, they might be quite common in Nature, but with short lifetimes and low energies. They also might be very small, existing only on the nano-level and hard to detect. Considering that the most logical place to look for charged, high-frequency non-radiating modes would be in powerful electrical discharges, such as found in lightning strokes, the surrounding phenomena might mask their occurrence. In the laboratory, strong microwave or laser (perhaps accompanied with D.C.) discharges, with possible extra-electron injection, might be conducive to non-radiative-mode production. Discharges in highly-ionizable dielectric gas mixtures such as cesium or Penning noble gas mixtures, under the above conditions may enhance the effect. In any case, detailed calculations and experiments might have to be done to determine optimal conditions such as discharge field strengths, gas density, frequency, electrode size, pre-ionization etc. The investigation of non-radiative-mode effects may be very fruitful in the future. For example: Rigid non-radiative composite "super-atomic particles" containing large numbers of fusible ions may be compressible in strong quadrupole fields without undergoing chaotic turbulence-like instabilities, and have lifetimes consistent with producing copious LENR reactions. Large-diameter modes, with significant lifetimes, might be capable of storing large amounts of energy, etc. The field seems to be wide open, hinging on simple experiments that may prove the basic principles. Cheers: Axil