Silicon by Localized Microwaves
Various experimental techniques have been employed in this study in an attempt to characterize the
microwave-excited plasmoid ejected by localized microwaves from silicon-based substrates in
atmospheric pressure environment. Each of these methods is limited in certain aspects, but their
ensemble provides a better insight of the fireball properties.
The fireball studied here is characterized as a partially ionized complex (dusty) plasma, as indicated
by the low electron density calculated (ne ~ 3 × 1018 m−3), the low temperatures measured (<1 eV), the
lack of spectral atomic ionization lines, and the presence of nanoparticles (nd ~ 1015 m−3) forming the
dusty plasmoid. These particles made of the substrate material seem to agglomerate into larger
structures in the micrometer scale. The effect of the fireball’s self-impedance matching tends to
maximize the absorbed power and to maintain its buoyancy. The dielectric permittivity of the buoyant
plasmoid is attributed both to the free electrons and to the charged dust particles. The chemical
reactions and combustion processes are evidenced by the radical production within the plasmoid.
These laboratory fireballs resemble natural BL, also in the aspects of aggregation and oxidation of
silicon micro-particles (e.g., [44,45]).
These findings, although requiring further studies, may advance the multi-disciplinary understanding
of the BL enigma. Beside the scientific aspects of the plasmoid and BL studies, derivatives of this work
are considered for applications, such as direct conversion of solids to powders in air atmosphere ,
microwave induced breakdown spectroscopy (MIBS) for material identification , ignition of
thermite reactions , environmental applications of the fireball UV and radical emission ,
developments of nano-battery concepts , micro-sphere production techniques (e.g., for optical
applications ), and microwave enhanced combustion processes.
Interesting study, especially the images of the produced spheres