This paper presents experimental characterization of plasmoids (fireballs) obtained by directing localized microwave power (<1 kW at 2.45 GHz) onto a silicon-based substrate in a microwave cavity. The plasmoid emerges up from the hotspot created in the solid substrate into the air within the microwave cavity. The experimental diagnostics employed for the fireball characterization in this study include measurements of microwave scattering, optical spectroscopy, small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Various characteristics of these plasmoids as dusty plasma are drawn by a theoretical analysis of the experimental observations. Aggregations of dust particles within the plasmoid are detected at nanometer and micrometer scales by both in-situ SAXS and ex-situ SEM measurements. The resemblance of these plasmoids to the natural ball-lightning (BL) phenomenon is discussed with regard to silicon nano-particle clustering and formation of slowly-oxidized silicon micro-spheres within the BL. Potential applications and practical derivatives of this study (e.g., direct conversion of solids to powders, material identification by breakdown spectroscopy (MIBS), thermite ignition, and combustion) are discussed.

Even a single excess electron or ion migrating on the surface of sensitive explosives can catalyze their gradual exothermic decomposition. Mechanisms underlying such a charge-induced gradual thermal decomposition of highly sensitive explosives can be different. If sensitive explosive is a polar liquid, intense charge-dipole attraction between excess surface charges and surrounding explosive molecules can result in repetitive attempts of solvation of these charges by polar explosive molecules. Every attempt of such uncompleted nonequilibrium solvation causes local exothermic decomposition of thermolabile polar molecules accompanied by further thermal jumping unsolvated excess charges to new surface sites. Thus, ionized mobile hot spots emerge on charged explosive surface. Stochastic migration of ionized hot spots on explosive surface causes gradual exothermic decomposition of the whole mass of the polar explosive. The similar gradual charge-catalyzed exothermic decomposition of both polar and nonpolar highly sensitive explosives can be also caused by intense charge-dipole attacks of surrounding water vapor molecules electrostatically attracted from ambient humid air and strongly accelerated towards charged sites on explosive surfaces. Emission of electrons, photons and heat from ionized hot spots randomly migrating on charged surface of highly sensitive explosive aerosol nanoparticles converts such particles into the form of short-circuited thermionic nanobatteries.

The physical mechanisms of periodic separation and relaxation of electric charges within aerosol particles possessing the properties the short-circuited batteries can be extremely diverse. With use of appropriate materials and dispersing methods, the electrochemical, thermoelectric, thermionic, pyroelectric, photoelectric, photo electronic emission, or even radionuclide-based emission micro and nano-batteries can be synthesized and be dispersed in the air as clouds self-assembed of the short-circuited aerosol batteries due to the inter-particle electromagnetic dipole-dipole attraction. Intense thermionic emission from ionized hot spots migrating on the relatively cold surface of charged explosive particles, can convert these particles into short-circuited thermionic batteries, turning an aerosol cloud consisting of such unipolar charged, gradually decomposing explosive particles into ball lightning. The slow exothermic decomposition of the highly sensitive explosive aerosol particles, catalyzed by excess ions on their surface, and also ion-catalyzed reactions of slow water vapor induced oxidation of charged combustible aerosol particles underlie two main classes of natural ball lightning. At the same time, the artificially generated clouds consisting of such unipolar charged aerosol nanobatteries, probably, can have some useful applications, not only military ones. In particular, it seems that high-performance pyroelectric fusion reactors could be created on the basis of such ball-shaped aerosol clouds self-assembled of pyroelectric nanocrystals - short-circuited pyroelectric nanobatteries.